Cutis

Evidence of human exposure to mercury dates as far back as the Egyptians in 1500 bc . ¹ The ancient Chinese believed mercury could prolong life, heal bones, and maintain vitality. ² Western medicine has utilized mercury in diuretics, laxatives, antibacterial agents, and antiseptics. ³ Health effects caused by chronic mercury exposure became increasingly apparent in the 1800s after hat makers who had inhaled mercuric nitrate vapors began to present with a host of neurologic symptoms, which is where the p hrase "mad as a hatter" was derived. ^4,5 In 1889, French neurologist Jean-Martin Charcot attributed rapid tremors to mercury poisoning. ⁶ By 1940, Kinnier Wilson ⁷ further characterized the effects of mercury, describing mercury-induced cognitive impairments. In the 1960s, Japanese researchers correlated elevated urinary mercury levels with an outbreak of Minamata disease, a condition characterized by tremors, sensory loss, ataxia, and visual constrictions. ⁸ The World Health Organization considers mercury to be one of the top 10 chemicals of major public health concern. ⁹

Mercury release in the environment primarily is a function of human activity, including coal-fired power plants, residential heating, and mining.^9,10 Mercury from these sources is commonly found in the sediment of lakes and bays, where it is enzymatically converted to methylmercury by aquatic microorganisms; subsequent food chain biomagnification results in elevated mercury levels in apex predators. Substantial release of mercury into the environment also can be attributed to health care facilities from their use of thermometers containing 0.5 to 3 g of elemental mercury,¹¹ blood pressure monitors, and medical waste incinerators.⁵

Mercury has been reported as the second most common cause of heavy metal poisoning after lead.¹² Standards from the US Food and Drug Administration dictate that methylmercury levels in fish and wheat products must not exceed 1 ppm.¹³ Most plant and animal food sources contain methylmercury at levels between 0.0001 and 0.01 ppm; mercury concentrations are especially high in tuna, averaging 0.4 ppm, while larger predatory fish contain levels in excess of 1 ppm.¹⁴ The use of mercury-containing cosmetic products also presents a substantial exposure risk to consumers.^5,10 In one study, 3.3% of skin-lightening creams and soaps purchased within the United States contained concentrations of mercury exceeding 1000 ppm.¹⁵

We describe a case of mercury toxicity resulting from intentional injection of liquid mercury into the right antecubital fossa in a suicide attempt.

Case Report

A 31-year-old woman presented to the family practice center for evaluation of a firm stained area on the skin of the right arm. She reported increasing anxiety, depression, tremors, irritability, and difficulty concentrating over the last 6 months. She denied headache and joint or muscle pain. Four years earlier, she had broken apart a thermometer and injected approximately 0.7 mL of its contents into the right arm in a suicide attempt. She intended to inject the thermometer’s contents directly into a vein, but the material instead entered the surrounding tissue. She denied notable pain or itching overlying the injection site. Her medications included aripiprazole and buspirone. She noted that she smoked half a pack of cigarettes per day and had a history of methamphetamine abuse. She was homeless and unemployed. Physical examination revealed an anxious tremulous woman with an erythematous to bluish gray, firm plaque on the right antecubital fossa (Figure 1). There were no notable tremors and no gait disturbance.

Her blood mercury level was greater than 100 µg/L and urine mercury was 477 µg/g (reference ranges, 1–8 μg/L and 4–5 μg/L, respectively). A radiograph of the right elbow area revealed scattered punctate foci of increased density within or overlying the anterolateral elbow soft tissues. She was diagnosed with mercury granuloma causing chronic mercury elevation. She underwent excision of the granuloma (Figure 2) with endovascular surgery via an elliptical incision. The patient was subsequently lost to follow-up.

Comment

Elemental mercury is a silver liquid at room temperature that spontaneously evaporates to form mercury vapor, an invisible, odorless, toxic gas. Accidental cutaneous exposure typically is safely managed by washing exposed skin with soap and water,¹⁶ though there is a potential risk for systemic absorption, especially when the skin is inflamed. When metallic mercury is subcutaneously injected, it is advised to promptly excise all subcutaneous areas containing mercury, regardless of any symptoms of systemic toxicity. Patients should subsequently be monitored for signs of both central nervous system (CNS) and renal deficits, undergo chelation therapy when systemic effects are apparent, and finally receive psychiatric consultation and treatment when necessary.¹⁷

Inorganic mercury compounds are formed when elemental mercury combines with sulfur or oxygen and often take the form of mercury salts, which appear as white crystals.¹⁶ These salts occur naturally in the environment and are used in pesticides, antiseptics, and skin-lightening creams and soaps.¹⁸

Methylmercury is a highly toxic, organic compound that is capable of crossing the placental and blood-brain barriers. It is the most common organic mercury compound found in the environment.¹⁶ Most humans have trace amounts of methylmercury in their bodies, typically as a result of consuming seafood.⁵

Exposure to mercury most commonly occurs through chronic consumption of methylmercury in seafood or acute inhalation of elemental mercury vapors.⁹ Iatrogenic cases of mercury exposure via injection also have been reported in the literature, including a case resulting in acute poisoning due to peritoneal lavage with mercury bichloride.¹⁹ Acute mercury-induced pulmonary damage typically resolves completely. However, there have been reported cases of exposure progressing to interstitial emphysema, pneumatocele, pneumothorax, pneumomediastinum, interstitial fibrosis, and chronic respiratory insufficiency, with examples of fatal acute respiratory distress syndrome being reported.^5,16,20 Although individuals who inhale mercury vapors initially may be unaware of exposure due to little upper airway irritation, symptoms following an initial acute exposure may include ptyalism, a metallic taste, dysphagia, enteritis, diarrhea, nausea, renal damage, and CNS effects.¹⁶ Additionally, exposure may lead to confusion with signs and symptoms of metal fume fever, including shortness of breath, pleuritic chest pain, stomatitis, lethargy, and vomiting.²⁰

Chronic exposure to mercury vapor can result in accumulation of mercury in the body, leading to neuropsychiatric, dermatologic, oropharyngeal, and renal manifestations. Sore throat, fever, headache, fatigue, dyspnea, chest pain, and pneumonitis are common.¹⁶ Typically, low-level exposure to elemental mercury does not lead to long-lasting health effects. However, individuals exposed to high-level elemental mercury vapors may require hospitalization. Treatment of acute mercury poisoning consists of removing the source of exposure, followed by cardiopulmonary support.¹⁶

Specific assays for mercury levels in blood and urine are useful to assess the level of exposure and risk to the patient. Blood mercury concentrations of 20 µg/L or below are considered within reference range; however, once blood and urine concentrations of mercury exceed 100 µg/L, clinical signs of acute mercury poisoning typically manifest.²¹ Chest radiographs can reveal pulmonary damage, while complete blood cell count, metabolic panel, and urinalysis can assess damage to other organs. Neuropsychiatric testing and nerve conduction studies may provide objective evidence of CNS toxicity. Assays for N-acetyl-β-D-glucosaminidase can provide an indication of early renal tubular dysfunction.¹⁶

Elemental mercury is not absorbed from the gastrointestinal tract, posing minimal risk for acute toxicity from ingestion. Generally, less than 10% of ingested inorganic mercury is absorbed from the gut, while elemental mercury is nonabsorbable.¹⁰ If an individual ingests a large amount of mercury, it may persist in the gastrointestinal tract for an extended period. Mercury is radiopaque, and abdominal radiographs should be obtained in all cases of ingestion.¹⁶

Mercury is toxic to the CNS and peripheral nervous system, resulting in erethism mercurialis, a constellation of neuropsychologic signs and symptoms including restlessness, irritability, insomnia, emotional lability, difficulty concentrating, and impaired memory. In severe cases, delirium and psychosis may develop. Other CNS effects include tremors, paresthesia, dysarthria, neuromuscular changes, headaches, polyneuropathy, and cerebellar ataxia, as well as ophthalmologic and audiologic impairment.^5,16

Upon inhalation exposure, patients with respiratory concerns should be given oxygen. Bronchospasms are treated with bronchodilators; however, if multiple chemical exposures are suspected, bronchial-sensitizing agents may pose additional risks. Corticosteroids and antibiotics have been recommended for treatment of chemical pneumonitis, but their efficacy has not been substantiated.¹⁶

Skin reactions associated with skin contact to elemental mercury are rare. However, hives and dermatitis have been observed following accidental contact with inorganic mercury compounds.⁵ Manifestation in children chronically exposed to mercury includes a nonallergic hypersensitivity (acrodynia),^5,17 which is characterized by pain and dusky pink discoloration in the hands and feet, most often seen in children chronically exposed to mercury absorbed from vapor inhalation or cutaneous exposure.¹⁶

Renal conditions associated with acute inhalation of elemental mercury vapor include proteinuria, nephrotic syndrome, temporary tubular dysfunction, acute tubular necrosis, and oliguric renal failure.¹⁶ Chronic exposure to inorganic mercury compounds also has been reported to cause renal damage.⁵ Chelation therapy should be performed for any symptomatic patient with a clear history of acute elemental mercury exposure.¹⁶ The most frequently used chelation agent in cases of acute inorganic mercury exposures is dimercaprol. In rare cases of mercury intoxication, hemodialysis is required in the treatment of renal failure and to expedite removal of dimercaprol-mercury complexes.¹⁶

Cardiovascular symptoms associated with acute inhalation of high levels of elemental mercury include tachycardia and hypertension.¹⁶ Increases in blood pressure, palpitations, and heart rate also have been observed in instances of acute elemental mercury exposure. Studies show that exposure to mercury increases both the risk for acute myocardial infarction as well as death from coronary heart and cardiovascular diseases.⁵

Conclusion

Mercury poisoning presents with varied neuropsychologic signs and symptoms. Our case provides insight into a unique route of exposure for mercury toxicity. In addition to the unusual presentation of a mercury granuloma, our case illustrates how surgical techniques can aid in removal of cutaneous reservoirs in the setting of percutaneous exposure.

Evidence of human exposure to mercury dates as far back as the Egyptians in 1500 bc . ¹ The ancient Chinese believed mercury could prolong life, heal bones, and maintain vitality. ² Western medicine has utilized mercury in diuretics, laxatives, antibacterial agents, and antiseptics. ³ Health effects caused by chronic mercury exposure became increasingly apparent in the 1800s after hat makers who had inhaled mercuric nitrate vapors began to present with a host of neurologic symptoms, which is where the p hrase "mad as a hatter" was derived. ^4,5 In 1889, French neurologist Jean-Martin Charcot attributed rapid tremors to mercury poisoning. ⁶ By 1940, Kinnier Wilson ⁷ further characterized the effects of mercury, describing mercury-induced cognitive impairments. In the 1960s, Japanese researchers correlated elevated urinary mercury levels with an outbreak of Minamata disease, a condition characterized by tremors, sensory loss, ataxia, and visual constrictions. ⁸ The World Health Organization considers mercury to be one of the top 10 chemicals of major public health concern. ⁹

Mercury release in the environment primarily is a function of human activity, including coal-fired power plants, residential heating, and mining.^9,10 Mercury from these sources is commonly found in the sediment of lakes and bays, where it is enzymatically converted to methylmercury by aquatic microorganisms; subsequent food chain biomagnification results in elevated mercury levels in apex predators. Substantial release of mercury into the environment also can be attributed to health care facilities from their use of thermometers containing 0.5 to 3 g of elemental mercury,¹¹ blood pressure monitors, and medical waste incinerators.⁵

Mercury has been reported as the second most common cause of heavy metal poisoning after lead.¹² Standards from the US Food and Drug Administration dictate that methylmercury levels in fish and wheat products must not exceed 1 ppm.¹³ Most plant and animal food sources contain methylmercury at levels between 0.0001 and 0.01 ppm; mercury concentrations are especially high in tuna, averaging 0.4 ppm, while larger predatory fish contain levels in excess of 1 ppm.¹⁴ The use of mercury-containing cosmetic products also presents a substantial exposure risk to consumers.^5,10 In one study, 3.3% of skin-lightening creams and soaps purchased within the United States contained concentrations of mercury exceeding 1000 ppm.¹⁵

We describe a case of mercury toxicity resulting from intentional injection of liquid mercury into the right antecubital fossa in a suicide attempt.

Case Report

A 31-year-old woman presented to the family practice center for evaluation of a firm stained area on the skin of the right arm. She reported increasing anxiety, depression, tremors, irritability, and difficulty concentrating over the last 6 months. She denied headache and joint or muscle pain. Four years earlier, she had broken apart a thermometer and injected approximately 0.7 mL of its contents into the right arm in a suicide attempt. She intended to inject the thermometer’s contents directly into a vein, but the material instead entered the surrounding tissue. She denied notable pain or itching overlying the injection site. Her medications included aripiprazole and buspirone. She noted that she smoked half a pack of cigarettes per day and had a history of methamphetamine abuse. She was homeless and unemployed. Physical examination revealed an anxious tremulous woman with an erythematous to bluish gray, firm plaque on the right antecubital fossa (Figure 1). There were no notable tremors and no gait disturbance.

Her blood mercury level was greater than 100 µg/L and urine mercury was 477 µg/g (reference ranges, 1–8 μg/L and 4–5 μg/L, respectively). A radiograph of the right elbow area revealed scattered punctate foci of increased density within or overlying the anterolateral elbow soft tissues. She was diagnosed with mercury granuloma causing chronic mercury elevation. She underwent excision of the granuloma (Figure 2) with endovascular surgery via an elliptical incision. The patient was subsequently lost to follow-up.

Comment

Elemental mercury is a silver liquid at room temperature that spontaneously evaporates to form mercury vapor, an invisible, odorless, toxic gas. Accidental cutaneous exposure typically is safely managed by washing exposed skin with soap and water,¹⁶ though there is a potential risk for systemic absorption, especially when the skin is inflamed. When metallic mercury is subcutaneously injected, it is advised to promptly excise all subcutaneous areas containing mercury, regardless of any symptoms of systemic toxicity. Patients should subsequently be monitored for signs of both central nervous system (CNS) and renal deficits, undergo chelation therapy when systemic effects are apparent, and finally receive psychiatric consultation and treatment when necessary.¹⁷

Inorganic mercury compounds are formed when elemental mercury combines with sulfur or oxygen and often take the form of mercury salts, which appear as white crystals.¹⁶ These salts occur naturally in the environment and are used in pesticides, antiseptics, and skin-lightening creams and soaps.¹⁸

Methylmercury is a highly toxic, organic compound that is capable of crossing the placental and blood-brain barriers. It is the most common organic mercury compound found in the environment.¹⁶ Most humans have trace amounts of methylmercury in their bodies, typically as a result of consuming seafood.⁵

Exposure to mercury most commonly occurs through chronic consumption of methylmercury in seafood or acute inhalation of elemental mercury vapors.⁹ Iatrogenic cases of mercury exposure via injection also have been reported in the literature, including a case resulting in acute poisoning due to peritoneal lavage with mercury bichloride.¹⁹ Acute mercury-induced pulmonary damage typically resolves completely. However, there have been reported cases of exposure progressing to interstitial emphysema, pneumatocele, pneumothorax, pneumomediastinum, interstitial fibrosis, and chronic respiratory insufficiency, with examples of fatal acute respiratory distress syndrome being reported.^5,16,20 Although individuals who inhale mercury vapors initially may be unaware of exposure due to little upper airway irritation, symptoms following an initial acute exposure may include ptyalism, a metallic taste, dysphagia, enteritis, diarrhea, nausea, renal damage, and CNS effects.¹⁶ Additionally, exposure may lead to confusion with signs and symptoms of metal fume fever, including shortness of breath, pleuritic chest pain, stomatitis, lethargy, and vomiting.²⁰

Chronic exposure to mercury vapor can result in accumulation of mercury in the body, leading to neuropsychiatric, dermatologic, oropharyngeal, and renal manifestations. Sore throat, fever, headache, fatigue, dyspnea, chest pain, and pneumonitis are common.¹⁶ Typically, low-level exposure to elemental mercury does not lead to long-lasting health effects. However, individuals exposed to high-level elemental mercury vapors may require hospitalization. Treatment of acute mercury poisoning consists of removing the source of exposure, followed by cardiopulmonary support.¹⁶

Specific assays for mercury levels in blood and urine are useful to assess the level of exposure and risk to the patient. Blood mercury concentrations of 20 µg/L or below are considered within reference range; however, once blood and urine concentrations of mercury exceed 100 µg/L, clinical signs of acute mercury poisoning typically manifest.²¹ Chest radiographs can reveal pulmonary damage, while complete blood cell count, metabolic panel, and urinalysis can assess damage to other organs. Neuropsychiatric testing and nerve conduction studies may provide objective evidence of CNS toxicity. Assays for N-acetyl-β-D-glucosaminidase can provide an indication of early renal tubular dysfunction.¹⁶

Elemental mercury is not absorbed from the gastrointestinal tract, posing minimal risk for acute toxicity from ingestion. Generally, less than 10% of ingested inorganic mercury is absorbed from the gut, while elemental mercury is nonabsorbable.¹⁰ If an individual ingests a large amount of mercury, it may persist in the gastrointestinal tract for an extended period. Mercury is radiopaque, and abdominal radiographs should be obtained in all cases of ingestion.¹⁶

Mercury is toxic to the CNS and peripheral nervous system, resulting in erethism mercurialis, a constellation of neuropsychologic signs and symptoms including restlessness, irritability, insomnia, emotional lability, difficulty concentrating, and impaired memory. In severe cases, delirium and psychosis may develop. Other CNS effects include tremors, paresthesia, dysarthria, neuromuscular changes, headaches, polyneuropathy, and cerebellar ataxia, as well as ophthalmologic and audiologic impairment.^5,16

Upon inhalation exposure, patients with respiratory concerns should be given oxygen. Bronchospasms are treated with bronchodilators; however, if multiple chemical exposures are suspected, bronchial-sensitizing agents may pose additional risks. Corticosteroids and antibiotics have been recommended for treatment of chemical pneumonitis, but their efficacy has not been substantiated.¹⁶

Skin reactions associated with skin contact to elemental mercury are rare. However, hives and dermatitis have been observed following accidental contact with inorganic mercury compounds.⁵ Manifestation in children chronically exposed to mercury includes a nonallergic hypersensitivity (acrodynia),^5,17 which is characterized by pain and dusky pink discoloration in the hands and feet, most often seen in children chronically exposed to mercury absorbed from vapor inhalation or cutaneous exposure.¹⁶

Renal conditions associated with acute inhalation of elemental mercury vapor include proteinuria, nephrotic syndrome, temporary tubular dysfunction, acute tubular necrosis, and oliguric renal failure.¹⁶ Chronic exposure to inorganic mercury compounds also has been reported to cause renal damage.⁵ Chelation therapy should be performed for any symptomatic patient with a clear history of acute elemental mercury exposure.¹⁶ The most frequently used chelation agent in cases of acute inorganic mercury exposures is dimercaprol. In rare cases of mercury intoxication, hemodialysis is required in the treatment of renal failure and to expedite removal of dimercaprol-mercury complexes.¹⁶

Cardiovascular symptoms associated with acute inhalation of high levels of elemental mercury include tachycardia and hypertension.¹⁶ Increases in blood pressure, palpitations, and heart rate also have been observed in instances of acute elemental mercury exposure. Studies show that exposure to mercury increases both the risk for acute myocardial infarction as well as death from coronary heart and cardiovascular diseases.⁵

Conclusion

Mercury poisoning presents with varied neuropsychologic signs and symptoms. Our case provides insight into a unique route of exposure for mercury toxicity. In addition to the unusual presentation of a mercury granuloma, our case illustrates how surgical techniques can aid in removal of cutaneous reservoirs in the setting of percutaneous exposure.

Evidence of human exposure to mercury dates as far back as the Egyptians in 1500 bc . ¹ The ancient Chinese believed mercury could prolong life, heal bones, and maintain vitality. ² Western medicine has utilized mercury in diuretics, laxatives, antibacterial agents, and antiseptics. ³ Health effects caused by chronic mercury exposure became increasingly apparent in the 1800s after hat makers who had inhaled mercuric nitrate vapors began to present with a host of neurologic symptoms, which is where the p hrase "mad as a hatter" was derived. ^4,5 In 1889, French neurologist Jean-Martin Charcot attributed rapid tremors to mercury poisoning. ⁶ By 1940, Kinnier Wilson ⁷ further characterized the effects of mercury, describing mercury-induced cognitive impairments. In the 1960s, Japanese researchers correlated elevated urinary mercury levels with an outbreak of Minamata disease, a condition characterized by tremors, sensory loss, ataxia, and visual constrictions. ⁸ The World Health Organization considers mercury to be one of the top 10 chemicals of major public health concern. ⁹

Mercury release in the environment primarily is a function of human activity, including coal-fired power plants, residential heating, and mining.^9,10 Mercury from these sources is commonly found in the sediment of lakes and bays, where it is enzymatically converted to methylmercury by aquatic microorganisms; subsequent food chain biomagnification results in elevated mercury levels in apex predators. Substantial release of mercury into the environment also can be attributed to health care facilities from their use of thermometers containing 0.5 to 3 g of elemental mercury,¹¹ blood pressure monitors, and medical waste incinerators.⁵

Mercury has been reported as the second most common cause of heavy metal poisoning after lead.¹² Standards from the US Food and Drug Administration dictate that methylmercury levels in fish and wheat products must not exceed 1 ppm.¹³ Most plant and animal food sources contain methylmercury at levels between 0.0001 and 0.01 ppm; mercury concentrations are especially high in tuna, averaging 0.4 ppm, while larger predatory fish contain levels in excess of 1 ppm.¹⁴ The use of mercury-containing cosmetic products also presents a substantial exposure risk to consumers.^5,10 In one study, 3.3% of skin-lightening creams and soaps purchased within the United States contained concentrations of mercury exceeding 1000 ppm.¹⁵

We describe a case of mercury toxicity resulting from intentional injection of liquid mercury into the right antecubital fossa in a suicide attempt.

Case Report

A 31-year-old woman presented to the family practice center for evaluation of a firm stained area on the skin of the right arm. She reported increasing anxiety, depression, tremors, irritability, and difficulty concentrating over the last 6 months. She denied headache and joint or muscle pain. Four years earlier, she had broken apart a thermometer and injected approximately 0.7 mL of its contents into the right arm in a suicide attempt. She intended to inject the thermometer’s contents directly into a vein, but the material instead entered the surrounding tissue. She denied notable pain or itching overlying the injection site. Her medications included aripiprazole and buspirone. She noted that she smoked half a pack of cigarettes per day and had a history of methamphetamine abuse. She was homeless and unemployed. Physical examination revealed an anxious tremulous woman with an erythematous to bluish gray, firm plaque on the right antecubital fossa (Figure 1). There were no notable tremors and no gait disturbance.

Her blood mercury level was greater than 100 µg/L and urine mercury was 477 µg/g (reference ranges, 1–8 μg/L and 4–5 μg/L, respectively). A radiograph of the right elbow area revealed scattered punctate foci of increased density within or overlying the anterolateral elbow soft tissues. She was diagnosed with mercury granuloma causing chronic mercury elevation. She underwent excision of the granuloma (Figure 2) with endovascular surgery via an elliptical incision. The patient was subsequently lost to follow-up.

Comment

Elemental mercury is a silver liquid at room temperature that spontaneously evaporates to form mercury vapor, an invisible, odorless, toxic gas. Accidental cutaneous exposure typically is safely managed by washing exposed skin with soap and water,¹⁶ though there is a potential risk for systemic absorption, especially when the skin is inflamed. When metallic mercury is subcutaneously injected, it is advised to promptly excise all subcutaneous areas containing mercury, regardless of any symptoms of systemic toxicity. Patients should subsequently be monitored for signs of both central nervous system (CNS) and renal deficits, undergo chelation therapy when systemic effects are apparent, and finally receive psychiatric consultation and treatment when necessary.¹⁷

Inorganic mercury compounds are formed when elemental mercury combines with sulfur or oxygen and often take the form of mercury salts, which appear as white crystals.¹⁶ These salts occur naturally in the environment and are used in pesticides, antiseptics, and skin-lightening creams and soaps.¹⁸

Methylmercury is a highly toxic, organic compound that is capable of crossing the placental and blood-brain barriers. It is the most common organic mercury compound found in the environment.¹⁶ Most humans have trace amounts of methylmercury in their bodies, typically as a result of consuming seafood.⁵

Exposure to mercury most commonly occurs through chronic consumption of methylmercury in seafood or acute inhalation of elemental mercury vapors.⁹ Iatrogenic cases of mercury exposure via injection also have been reported in the literature, including a case resulting in acute poisoning due to peritoneal lavage with mercury bichloride.¹⁹ Acute mercury-induced pulmonary damage typically resolves completely. However, there have been reported cases of exposure progressing to interstitial emphysema, pneumatocele, pneumothorax, pneumomediastinum, interstitial fibrosis, and chronic respiratory insufficiency, with examples of fatal acute respiratory distress syndrome being reported.^5,16,20 Although individuals who inhale mercury vapors initially may be unaware of exposure due to little upper airway irritation, symptoms following an initial acute exposure may include ptyalism, a metallic taste, dysphagia, enteritis, diarrhea, nausea, renal damage, and CNS effects.¹⁶ Additionally, exposure may lead to confusion with signs and symptoms of metal fume fever, including shortness of breath, pleuritic chest pain, stomatitis, lethargy, and vomiting.²⁰

Chronic exposure to mercury vapor can result in accumulation of mercury in the body, leading to neuropsychiatric, dermatologic, oropharyngeal, and renal manifestations. Sore throat, fever, headache, fatigue, dyspnea, chest pain, and pneumonitis are common.¹⁶ Typically, low-level exposure to elemental mercury does not lead to long-lasting health effects. However, individuals exposed to high-level elemental mercury vapors may require hospitalization. Treatment of acute mercury poisoning consists of removing the source of exposure, followed by cardiopulmonary support.¹⁶

Specific assays for mercury levels in blood and urine are useful to assess the level of exposure and risk to the patient. Blood mercury concentrations of 20 µg/L or below are considered within reference range; however, once blood and urine concentrations of mercury exceed 100 µg/L, clinical signs of acute mercury poisoning typically manifest.²¹ Chest radiographs can reveal pulmonary damage, while complete blood cell count, metabolic panel, and urinalysis can assess damage to other organs. Neuropsychiatric testing and nerve conduction studies may provide objective evidence of CNS toxicity. Assays for N-acetyl-β-D-glucosaminidase can provide an indication of early renal tubular dysfunction.¹⁶

Elemental mercury is not absorbed from the gastrointestinal tract, posing minimal risk for acute toxicity from ingestion. Generally, less than 10% of ingested inorganic mercury is absorbed from the gut, while elemental mercury is nonabsorbable.¹⁰ If an individual ingests a large amount of mercury, it may persist in the gastrointestinal tract for an extended period. Mercury is radiopaque, and abdominal radiographs should be obtained in all cases of ingestion.¹⁶

Mercury is toxic to the CNS and peripheral nervous system, resulting in erethism mercurialis, a constellation of neuropsychologic signs and symptoms including restlessness, irritability, insomnia, emotional lability, difficulty concentrating, and impaired memory. In severe cases, delirium and psychosis may develop. Other CNS effects include tremors, paresthesia, dysarthria, neuromuscular changes, headaches, polyneuropathy, and cerebellar ataxia, as well as ophthalmologic and audiologic impairment.^5,16

Upon inhalation exposure, patients with respiratory concerns should be given oxygen. Bronchospasms are treated with bronchodilators; however, if multiple chemical exposures are suspected, bronchial-sensitizing agents may pose additional risks. Corticosteroids and antibiotics have been recommended for treatment of chemical pneumonitis, but their efficacy has not been substantiated.¹⁶

Skin reactions associated with skin contact to elemental mercury are rare. However, hives and dermatitis have been observed following accidental contact with inorganic mercury compounds.⁵ Manifestation in children chronically exposed to mercury includes a nonallergic hypersensitivity (acrodynia),^5,17 which is characterized by pain and dusky pink discoloration in the hands and feet, most often seen in children chronically exposed to mercury absorbed from vapor inhalation or cutaneous exposure.¹⁶

Renal conditions associated with acute inhalation of elemental mercury vapor include proteinuria, nephrotic syndrome, temporary tubular dysfunction, acute tubular necrosis, and oliguric renal failure.¹⁶ Chronic exposure to inorganic mercury compounds also has been reported to cause renal damage.⁵ Chelation therapy should be performed for any symptomatic patient with a clear history of acute elemental mercury exposure.¹⁶ The most frequently used chelation agent in cases of acute inorganic mercury exposures is dimercaprol. In rare cases of mercury intoxication, hemodialysis is required in the treatment of renal failure and to expedite removal of dimercaprol-mercury complexes.¹⁶

Cardiovascular symptoms associated with acute inhalation of high levels of elemental mercury include tachycardia and hypertension.¹⁶ Increases in blood pressure, palpitations, and heart rate also have been observed in instances of acute elemental mercury exposure. Studies show that exposure to mercury increases both the risk for acute myocardial infarction as well as death from coronary heart and cardiovascular diseases.⁵

Conclusion

Mercury poisoning presents with varied neuropsychologic signs and symptoms. Our case provides insight into a unique route of exposure for mercury toxicity. In addition to the unusual presentation of a mercury granuloma, our case illustrates how surgical techniques can aid in removal of cutaneous reservoirs in the setting of percutaneous exposure.

Health care–specific (eg, Healthgrades, Zocdoc, Vitals, WebMD) and general consumer websites (eg, Google, Yelp) are popular platforms for patients to find physicians, schedule appointments, and review physician experiences. Patients find ratings on these websites more trustworthy than standardized surveys distributed by hospitals, but many physicians do not trust the reviews on these sites. For example, in a survey of both physicians (n=828) and patients (n=494), 36% of physicians trusted online reviews compared to 57% of patients.¹ The objective of this study was to determine if health care–specific or general consumer websites more accurately reflect overall patient sentiment. This knowledge can help physicians who are seeking to improve the patient experience understand which websites have more accurate and trustworthy reviews.

Methods

A list of dermatologists from the top 10 most and least dermatologist–dense areas in the United States was compiled to examine different physician populations.² Equal numbers of male and female dermatologists were randomly selected from the most dense areas. All physicians were included from the least dense areas because of limited sample size. Ratings were collected from websites most likely to appear on the first page of a Google search for a physician name, as these are most likely to be seen by patients. Descriptive statistics were generated to describe the study population; mean and median physician rating (using a scale of 1–5); SD; and minimum, maximum, and interquartile ranges. Spearman correlation coefficients were generated to examine the strength of association between ratings from website pairs. P<.05 was considered statistically significant, with analyses performed in R (3.6.2) for Windows (the R Foundation).

Results

A total of 167 representative physicians were included in this analysis; 141 from the most dense areas, and 26 from the least dense areas. The lowest average ratings for the entire sample and most dermatologist–dense areas were found on Yelp (3.61 and 3.60, respectively), and the lowest ratings in the least dermatologist–dense areas were found on Google (3.45)(Table 1). Correlation coefficient values were lowest for Zocdoc and Healthgrades (0.263) and highest for Vitals and WebMD (0.963)(Table 2). The health care–specific sites were closer to the overall average (4.06) than the general consumer sites (eFigure).

Comment

Although dermatologist ratings on each site had a broad range, we found that patients typically expressed negative interactions on general consumer websites rather than health care–specific websites. When comparing the ratings of the same group of dermatologists across different sites, ratings on health care–specific sites had a higher degree of correlation, with physician ratings more similar between 2 health care–specific sites and less similar between a health care–specific and a general consumer website. This pattern was consistent in both dermatologist-dense and dermatologist-poor areas, despite patients having varying levels of access to dermatologic care and medical resources and potentially different regional preferences of consumer websites. Taken together, these findings imply that health care–specific websites more consistently reflect overall patient sentiment.

Although one 2016 study comparing reviews of dermatology practices on Zocdoc and Yelp also demonstrated lower average ratings on Yelp,³ our study suggests that this trend is not isolated to these 2 sites but can be seen when comparing many health care–specific sites vs general consumer sites.

Our study compared ratings of dermatologists among popular websites to understand those that are most representative of patient attitudes toward physicians. These findings are important because online reviews reflect the entire patient experience, not just the patient-physician interaction, which may explain why physician scores on standardized questionnaires, such as Press Ganey surveys, do not correlate well with their online reviews.⁴ In a study comparing 98 physicians with negative online ratings to 82 physicians in similar departments with positive ratings, there was no significant difference in scores on patient-physician interaction questions on the Press Ganey survey.⁵ However, physicians who received negative online reviews scored lower on Press Ganey questions related to nonphysician interactions (eg, office cleanliness, interactions with staff).

The current study was subject to several limitations. Our analysis included all physicians in our random selection without accounting for those physicians with a greater online presence who might be more cognizant of these ratings and try to manipulate them through a reputation-management company or public relations consultant.

Conclusion

Our study suggests that consumer websites are not primarily used by disgruntled patients wishing to express grievances; instead, on average, most physicians received positive reviews. Furthermore, health care–specific websites show a higher degree of concordance than and may more accurately reflect overall patient attitudes toward their physicians than general consumer sites. Reviews from these health care–specific sites may be more helpful than general consumer websites in allowing physicians to understand patient sentiment and improve patient experiences.

Health care–specific (eg, Healthgrades, Zocdoc, Vitals, WebMD) and general consumer websites (eg, Google, Yelp) are popular platforms for patients to find physicians, schedule appointments, and review physician experiences. Patients find ratings on these websites more trustworthy than standardized surveys distributed by hospitals, but many physicians do not trust the reviews on these sites. For example, in a survey of both physicians (n=828) and patients (n=494), 36% of physicians trusted online reviews compared to 57% of patients.¹ The objective of this study was to determine if health care–specific or general consumer websites more accurately reflect overall patient sentiment. This knowledge can help physicians who are seeking to improve the patient experience understand which websites have more accurate and trustworthy reviews.

Methods

A list of dermatologists from the top 10 most and least dermatologist–dense areas in the United States was compiled to examine different physician populations.² Equal numbers of male and female dermatologists were randomly selected from the most dense areas. All physicians were included from the least dense areas because of limited sample size. Ratings were collected from websites most likely to appear on the first page of a Google search for a physician name, as these are most likely to be seen by patients. Descriptive statistics were generated to describe the study population; mean and median physician rating (using a scale of 1–5); SD; and minimum, maximum, and interquartile ranges. Spearman correlation coefficients were generated to examine the strength of association between ratings from website pairs. P<.05 was considered statistically significant, with analyses performed in R (3.6.2) for Windows (the R Foundation).

Results

A total of 167 representative physicians were included in this analysis; 141 from the most dense areas, and 26 from the least dense areas. The lowest average ratings for the entire sample and most dermatologist–dense areas were found on Yelp (3.61 and 3.60, respectively), and the lowest ratings in the least dermatologist–dense areas were found on Google (3.45)(Table 1). Correlation coefficient values were lowest for Zocdoc and Healthgrades (0.263) and highest for Vitals and WebMD (0.963)(Table 2). The health care–specific sites were closer to the overall average (4.06) than the general consumer sites (eFigure).

Comment

Although dermatologist ratings on each site had a broad range, we found that patients typically expressed negative interactions on general consumer websites rather than health care–specific websites. When comparing the ratings of the same group of dermatologists across different sites, ratings on health care–specific sites had a higher degree of correlation, with physician ratings more similar between 2 health care–specific sites and less similar between a health care–specific and a general consumer website. This pattern was consistent in both dermatologist-dense and dermatologist-poor areas, despite patients having varying levels of access to dermatologic care and medical resources and potentially different regional preferences of consumer websites. Taken together, these findings imply that health care–specific websites more consistently reflect overall patient sentiment.

Although one 2016 study comparing reviews of dermatology practices on Zocdoc and Yelp also demonstrated lower average ratings on Yelp,³ our study suggests that this trend is not isolated to these 2 sites but can be seen when comparing many health care–specific sites vs general consumer sites.

Our study compared ratings of dermatologists among popular websites to understand those that are most representative of patient attitudes toward physicians. These findings are important because online reviews reflect the entire patient experience, not just the patient-physician interaction, which may explain why physician scores on standardized questionnaires, such as Press Ganey surveys, do not correlate well with their online reviews.⁴ In a study comparing 98 physicians with negative online ratings to 82 physicians in similar departments with positive ratings, there was no significant difference in scores on patient-physician interaction questions on the Press Ganey survey.⁵ However, physicians who received negative online reviews scored lower on Press Ganey questions related to nonphysician interactions (eg, office cleanliness, interactions with staff).

The current study was subject to several limitations. Our analysis included all physicians in our random selection without accounting for those physicians with a greater online presence who might be more cognizant of these ratings and try to manipulate them through a reputation-management company or public relations consultant.

Conclusion

Our study suggests that consumer websites are not primarily used by disgruntled patients wishing to express grievances; instead, on average, most physicians received positive reviews. Furthermore, health care–specific websites show a higher degree of concordance than and may more accurately reflect overall patient attitudes toward their physicians than general consumer sites. Reviews from these health care–specific sites may be more helpful than general consumer websites in allowing physicians to understand patient sentiment and improve patient experiences.

Health care–specific (eg, Healthgrades, Zocdoc, Vitals, WebMD) and general consumer websites (eg, Google, Yelp) are popular platforms for patients to find physicians, schedule appointments, and review physician experiences. Patients find ratings on these websites more trustworthy than standardized surveys distributed by hospitals, but many physicians do not trust the reviews on these sites. For example, in a survey of both physicians (n=828) and patients (n=494), 36% of physicians trusted online reviews compared to 57% of patients.¹ The objective of this study was to determine if health care–specific or general consumer websites more accurately reflect overall patient sentiment. This knowledge can help physicians who are seeking to improve the patient experience understand which websites have more accurate and trustworthy reviews.

Methods

A list of dermatologists from the top 10 most and least dermatologist–dense areas in the United States was compiled to examine different physician populations.² Equal numbers of male and female dermatologists were randomly selected from the most dense areas. All physicians were included from the least dense areas because of limited sample size. Ratings were collected from websites most likely to appear on the first page of a Google search for a physician name, as these are most likely to be seen by patients. Descriptive statistics were generated to describe the study population; mean and median physician rating (using a scale of 1–5); SD; and minimum, maximum, and interquartile ranges. Spearman correlation coefficients were generated to examine the strength of association between ratings from website pairs. P<.05 was considered statistically significant, with analyses performed in R (3.6.2) for Windows (the R Foundation).

Results

A total of 167 representative physicians were included in this analysis; 141 from the most dense areas, and 26 from the least dense areas. The lowest average ratings for the entire sample and most dermatologist–dense areas were found on Yelp (3.61 and 3.60, respectively), and the lowest ratings in the least dermatologist–dense areas were found on Google (3.45)(Table 1). Correlation coefficient values were lowest for Zocdoc and Healthgrades (0.263) and highest for Vitals and WebMD (0.963)(Table 2). The health care–specific sites were closer to the overall average (4.06) than the general consumer sites (eFigure).

Comment

Although dermatologist ratings on each site had a broad range, we found that patients typically expressed negative interactions on general consumer websites rather than health care–specific websites. When comparing the ratings of the same group of dermatologists across different sites, ratings on health care–specific sites had a higher degree of correlation, with physician ratings more similar between 2 health care–specific sites and less similar between a health care–specific and a general consumer website. This pattern was consistent in both dermatologist-dense and dermatologist-poor areas, despite patients having varying levels of access to dermatologic care and medical resources and potentially different regional preferences of consumer websites. Taken together, these findings imply that health care–specific websites more consistently reflect overall patient sentiment.

Although one 2016 study comparing reviews of dermatology practices on Zocdoc and Yelp also demonstrated lower average ratings on Yelp,³ our study suggests that this trend is not isolated to these 2 sites but can be seen when comparing many health care–specific sites vs general consumer sites.

Our study compared ratings of dermatologists among popular websites to understand those that are most representative of patient attitudes toward physicians. These findings are important because online reviews reflect the entire patient experience, not just the patient-physician interaction, which may explain why physician scores on standardized questionnaires, such as Press Ganey surveys, do not correlate well with their online reviews.⁴ In a study comparing 98 physicians with negative online ratings to 82 physicians in similar departments with positive ratings, there was no significant difference in scores on patient-physician interaction questions on the Press Ganey survey.⁵ However, physicians who received negative online reviews scored lower on Press Ganey questions related to nonphysician interactions (eg, office cleanliness, interactions with staff).

The current study was subject to several limitations. Our analysis included all physicians in our random selection without accounting for those physicians with a greater online presence who might be more cognizant of these ratings and try to manipulate them through a reputation-management company or public relations consultant.

Conclusion

Our study suggests that consumer websites are not primarily used by disgruntled patients wishing to express grievances; instead, on average, most physicians received positive reviews. Furthermore, health care–specific websites show a higher degree of concordance than and may more accurately reflect overall patient attitudes toward their physicians than general consumer sites. Reviews from these health care–specific sites may be more helpful than general consumer websites in allowing physicians to understand patient sentiment and improve patient experiences.

Apremilast is a small-molecule biologic approved by the US Food and Drug Administration (FDA) for use in plaque psoriasis, psoriatic arthritis, and Behçet disease.^1-6 Although apremilast is seemingly a less favorable choice for treating psoriasis in the era of injectable biologics, the drug is an important option for patients in the military. In recent months, apremilast also emerged as one of a few systemic medications recommended for the treatment of psoriasis and other dermatologic conditions during the COVID-19 pandemic.⁷

In this article, we review on-label indications and off-label uses for apremilast; highlight the importance of apremilast for managing psoriasis in the military population; and propose other patient populations in whom the use of apremilast is favorable. We also present a case report that highlights and embodies the benefit of apremilast for military service members.

CASE REPORT

A 28-year-old active-duty male US Navy service member developed extensive guttate psoriasis in a distribution too wide to manage with topical medication (Figure, A–C). His condition did not improve with a trial of oral antibiotics, and he reported itch that affected his sleep. He denied new joint pain, swelling, or deformity.

A review of the patient’s service history revealed that he was serving aboard a guided-missile cruiser ship for a tour extending an additional 2 years. Limited medical resources and lack of refrigeration made the use of injectable biologics, such as adalimumab, infeasible. Furthermore, the patient was too critical to the mission to be transported frequently off the ship to a higher level of care for injection of medication. He also had trouble returning for appointments and refills because of the high operational tempo of his command.

After discussion with the patient, oral apremilast was started at 30 mg/d and titrated up to the standard dosing of 30 mg twice daily, with excellent results by 3 months after he started therapy (Figure, D–F).

COMMENT

We reviewed the research on apremilast for its approved indications, including psoriasis; its off-label uses; and strategies for using the drug to treat psoriasis and other dermatologic conditions in military populations. The most recent evidence regarding the use of apremilast in dermatology, rheumatology, and other medical specialties was assessed using published English-language research data and review articles. We conducted a PubMed search of articles indexed for MEDLINE using the following terms: apremilast, Otezla, psoriasis, psoriatic arthritis, arthritis, off-label, Behçet’s, hidradenitis suppurativa, military, and armed forces. We also reviewed citations within relevant articles to identify additional relevant sources.

Off-label uses reviewed here are based on data from randomized controlled trials, large open-label trials, and large prospective case series. Articles with less evidence are not included in this review.

On-Label Usage Profile

Apremilast is an orally administered, small-molecule inhibitor of phosphodiesterase 4. Small-molecule inhibitors are a class of medications with low molecular weight, high stability, and short half-life. They act intracellularly to modulate proinflammatory states through regulation of the proinflammatory cytokine milieu.

Apremilast has been approved by the FDA for use in adult psoriasis and psoriatic arthritis since 2014 and for use in treating oral ulcers of Behçet disease since 2019.^1-3,5,6 Recently, a phase 2, multicenter, open-label study on the use of apremilast in pediatric psoriasis patients (aged 12–17 years) demonstrated a similar safety profile with weight-based dosing⁸; phase 3 trials in this population are in the recruitment phase (ClinicalTrials.gov Identifier NCT03701763).

Because information regarding its use in pregnancy is limited, apremilast is not recommended in this population. It is unknown whether apremilast is present in breast milk; although the manufacturer does not make explicit recommendations regarding use during breastfeeding, an expert panel reviewing management of psoriasis in pregnant and breastfeeding women recommended avoiding its use while breastfeeding.⁹

Common Adverse Effects

Common adverse effects (AEs) include weight loss (>5% total body weight in 5% of patients; 5%–10% of total body weight in 10%–12% of patients; and ≥10% total body weight in 2% of patients), diarrhea and nausea, headache, and upper respiratory tract infection.^10,11 Gastrointestinal AEs tend to be self-limited and improve or resolve after the first few weeks of therapy. Caution is advised in patients older than 65 years and in those at risk for hypotension or volume depletion. Although depressed mood is a rare AE (<1%), apremilast should be used cautiously in patients with a history of depression or suicidal ideation. Weight loss generally is self-limited; routine monitoring of weight is recommended.¹¹

Apremilast in Psoriasis and Psoriatic Arthritis

Psoriasis
The ESTEEM trials established the safety and efficacy of apremilast for use in psoriasis.^2,3 In a phase 3, multicenter, double-blind, placebo-controlled trial of 844 patients, apremilast demonstrated a statistically significant 75% or greater reduction from the baseline psoriasis area and severity index score (PASI-75) in 33.1% of patients receiving the medication compared to 5.3% of those receiving placebo.² Data from real-world practice (outside constraints of clinical trials) suggest slightly greater efficacy than was demonstrated in the ESTEEM trials.

A recently published retrospective, cross-sectional study of 480 patients with psoriasis treated with apremilast reported that 48.6% of patients continuing therapy for a mean (SD) of 6 (1) months achieved PASI-75. Furthermore, the mean dermatology life quality index (DLQI) score of the surveyed population decreased from 13.4 at initiation of treatment to 5.7 at 6 (1) months of treatment—a marked improvement in quality of life.¹² Other single-center and smaller study populations also have suggested increased real-world benefit.^13,14

Nonetheless, the rate and degree of clearance of plaques with apremilast seem to lag behind what is observed with many of the biologics and traditional medications employed to treat psoriasis.^15-19 Furthermore, indirect cost analysis comparisons suggest a much higher cost per level of PASI for apremilast compared to several biologics and to methotrexate.^20,21 A study that used indirect methods of comparison to analyze the comparative cost and efficacy of apremilast and methotrexate found no evidence of greater efficacy for apremilast and that the incremental cost to achieve 1 additional PASI-75 responder by using apremilast is $187,888 annually.²¹

Psoriatic Arthritis
The PALACE clinical trials 1, 2, and 3 assessed the efficacy of apremilast in patients who had prior treatment with conventional disease-modifying antirheumatic drugs or biologics, or both. PALACE 4 evaluated efficacy in treatment-naïve patients; standard dosing of apremilast was found to produce improvement in psoriatic arthritis in treatment-naïve and non–treatment-naïve patients.^4-6,22 In the 24-week placebo-controlled phase of the PALACE 1 trial, the American College of Rheumatology (ACR) baseline composite measurement of 20% disease improvement, or ACR20, was achieved in 40% of patients randomized to the standard dosing regimen compared to 19% of patients receiving placebo, a statistically significant result (P<.001).²²

Evaluation of long-term study data is beyond the scope of this review, but those data suggest that disease outcomes continue to improve the longer therapy is utilized, with a greater percentage of patients achieving ACR20 as well as ACR50 (50% improvement) and ACR70 (70% improvement) responses. Indirect comparisons analyzing the cost and effectiveness for adalimumab, apremilast, and methotrexate in patients with psoriatic arthritis found that apremilast was less effective than adalimumab and as efficacious as methotrexate, though apremilast carries the highest price tag of these drugs.²³

Off-Label Uses

Ease of oral administration and a favorable safety profile have prompted off-label study of apremilast in other inflammatory skin diseases, including atopic dermatitis, hidradenitis suppurativa, lichen planus, rosacea, alopecia areata, and cutaneous sarcoidosis. Publications with a minimum case series of 10 patients are included in the Table.^24-32

Use in the Military and Beyond

Psoriasis and other inflammatory skin conditions are common in the military and can greatly hinder a service member’s ability to perform their duties and remain ready to deploy. A history of psoriasis is disqualifying for military recruits, but early entry into service, misdiagnosis, and low or no burden of disease at time of entry into the service all contribute to a substantial population of active-duty service members who require treatment of psoriasis.³³ Necessity dictates that treatment of this condition extend to theater operations; from 2008 to 2015, more than 3600 soldiers sought care for psoriasis while deployed to a combat theater.³⁴

In some cases, poorly controlled inflammatory skin conditions lead to medical separation.³³ Although there are limited data on the use of apremilast in the military, its use during deployment for the treatment of psoriasis and psoriatic arthritis has been reported, with the great majority of service members retaining their deployable status even 1 year after the study period.³⁵

The ideal medication for deployable military personnel should have low toxicity, simple storage, and minimal monitoring requirements, and it should not expose a service member to increased risk while in a combat theater. Worldwide deployability is a requirement for most military occupations. The risk for immunosuppression with targeted immune therapy must be fully weighed, as certain duty stations and deployments might increase the risk for exposure to Mycobacterium tuberculosis, endemic mycopathogens, hepatitis C virus, HIV, Leishmania, and Strongyloides.³⁴

Furthermore, the tumor necrosis factor α inhibitors and IL-17 and IL-23 blockers used to treat psoriasis all require refrigeration; often, this requirement cannot be met in austere overseas settings. Additional requirements for laboratory monitoring, titration of medications, and frequent office visits might prohibit a service member from performing their duties, which, in turn, is detrimental to military readiness and the career of that service member.

Last, the Centers for Disease Control and Prevention recommend avoiding live virus vaccination while taking targeted immune therapy because of safety and effectiveness concerns during immunosuppression.³⁶ This recommendation might disqualify military personnel from deployment to certain locations that require the protection that such vaccines afford. Therefore, apremilast is an ideal option for the military patient population, with many military-specific advantages.

Of course, the military is not the only population in whom ease of use and storage and simplified monitoring parameters are essential. Benefits of apremilast also may translate to patients who are placed in austere conditions or who participate in extended worldwide travel for work or leisure, such as government contractors who deploy in support of military operations, firefighters or national park employees who spend extended periods in resource-limited settings, and foreign-aid workers and diplomats who are engaged in frequent travel around the world. Furthermore, travel to certain regions might increase the risk for exposure to atypical pathogens as well as the desire for a therapeutic option that does not have potential to suppress the immune system. This subset of psoriasis patients might be better treated with novel agents such as apremilast than other drugs that would be the presumed standard of care in a domestic setting.

Final Thoughts

The benefits of apremilast translate to all patients in austere environments with limited resources and during times when immune function is of utmost concern. For military service members and many civilians in austere environments worldwide, apremilast could be considered a first-line systemic agent for psoriasis and psoriatic arthritis. In patients unable to use or tolerate other treatments, apremilast can be considered for off-label therapy (Table^24-32). There are times when the approach to prescribing must look beyond primary efficacy, AE profile, and cost—to include occupation, environment, or duties—to select the optimal medication for a patient.

Apremilast is a small-molecule biologic approved by the US Food and Drug Administration (FDA) for use in plaque psoriasis, psoriatic arthritis, and Behçet disease.^1-6 Although apremilast is seemingly a less favorable choice for treating psoriasis in the era of injectable biologics, the drug is an important option for patients in the military. In recent months, apremilast also emerged as one of a few systemic medications recommended for the treatment of psoriasis and other dermatologic conditions during the COVID-19 pandemic.⁷

In this article, we review on-label indications and off-label uses for apremilast; highlight the importance of apremilast for managing psoriasis in the military population; and propose other patient populations in whom the use of apremilast is favorable. We also present a case report that highlights and embodies the benefit of apremilast for military service members.

CASE REPORT

A 28-year-old active-duty male US Navy service member developed extensive guttate psoriasis in a distribution too wide to manage with topical medication (Figure, A–C). His condition did not improve with a trial of oral antibiotics, and he reported itch that affected his sleep. He denied new joint pain, swelling, or deformity.

A review of the patient’s service history revealed that he was serving aboard a guided-missile cruiser ship for a tour extending an additional 2 years. Limited medical resources and lack of refrigeration made the use of injectable biologics, such as adalimumab, infeasible. Furthermore, the patient was too critical to the mission to be transported frequently off the ship to a higher level of care for injection of medication. He also had trouble returning for appointments and refills because of the high operational tempo of his command.

After discussion with the patient, oral apremilast was started at 30 mg/d and titrated up to the standard dosing of 30 mg twice daily, with excellent results by 3 months after he started therapy (Figure, D–F).

COMMENT

We reviewed the research on apremilast for its approved indications, including psoriasis; its off-label uses; and strategies for using the drug to treat psoriasis and other dermatologic conditions in military populations. The most recent evidence regarding the use of apremilast in dermatology, rheumatology, and other medical specialties was assessed using published English-language research data and review articles. We conducted a PubMed search of articles indexed for MEDLINE using the following terms: apremilast, Otezla, psoriasis, psoriatic arthritis, arthritis, off-label, Behçet’s, hidradenitis suppurativa, military, and armed forces. We also reviewed citations within relevant articles to identify additional relevant sources.

Off-label uses reviewed here are based on data from randomized controlled trials, large open-label trials, and large prospective case series. Articles with less evidence are not included in this review.

On-Label Usage Profile

Apremilast is an orally administered, small-molecule inhibitor of phosphodiesterase 4. Small-molecule inhibitors are a class of medications with low molecular weight, high stability, and short half-life. They act intracellularly to modulate proinflammatory states through regulation of the proinflammatory cytokine milieu.

Apremilast has been approved by the FDA for use in adult psoriasis and psoriatic arthritis since 2014 and for use in treating oral ulcers of Behçet disease since 2019.^1-3,5,6 Recently, a phase 2, multicenter, open-label study on the use of apremilast in pediatric psoriasis patients (aged 12–17 years) demonstrated a similar safety profile with weight-based dosing⁸; phase 3 trials in this population are in the recruitment phase (ClinicalTrials.gov Identifier NCT03701763).

Because information regarding its use in pregnancy is limited, apremilast is not recommended in this population. It is unknown whether apremilast is present in breast milk; although the manufacturer does not make explicit recommendations regarding use during breastfeeding, an expert panel reviewing management of psoriasis in pregnant and breastfeeding women recommended avoiding its use while breastfeeding.⁹

Common Adverse Effects

Common adverse effects (AEs) include weight loss (>5% total body weight in 5% of patients; 5%–10% of total body weight in 10%–12% of patients; and ≥10% total body weight in 2% of patients), diarrhea and nausea, headache, and upper respiratory tract infection.^10,11 Gastrointestinal AEs tend to be self-limited and improve or resolve after the first few weeks of therapy. Caution is advised in patients older than 65 years and in those at risk for hypotension or volume depletion. Although depressed mood is a rare AE (<1%), apremilast should be used cautiously in patients with a history of depression or suicidal ideation. Weight loss generally is self-limited; routine monitoring of weight is recommended.¹¹

Apremilast in Psoriasis and Psoriatic Arthritis

Psoriasis
The ESTEEM trials established the safety and efficacy of apremilast for use in psoriasis.^2,3 In a phase 3, multicenter, double-blind, placebo-controlled trial of 844 patients, apremilast demonstrated a statistically significant 75% or greater reduction from the baseline psoriasis area and severity index score (PASI-75) in 33.1% of patients receiving the medication compared to 5.3% of those receiving placebo.² Data from real-world practice (outside constraints of clinical trials) suggest slightly greater efficacy than was demonstrated in the ESTEEM trials.

A recently published retrospective, cross-sectional study of 480 patients with psoriasis treated with apremilast reported that 48.6% of patients continuing therapy for a mean (SD) of 6 (1) months achieved PASI-75. Furthermore, the mean dermatology life quality index (DLQI) score of the surveyed population decreased from 13.4 at initiation of treatment to 5.7 at 6 (1) months of treatment—a marked improvement in quality of life.¹² Other single-center and smaller study populations also have suggested increased real-world benefit.^13,14

Nonetheless, the rate and degree of clearance of plaques with apremilast seem to lag behind what is observed with many of the biologics and traditional medications employed to treat psoriasis.^15-19 Furthermore, indirect cost analysis comparisons suggest a much higher cost per level of PASI for apremilast compared to several biologics and to methotrexate.^20,21 A study that used indirect methods of comparison to analyze the comparative cost and efficacy of apremilast and methotrexate found no evidence of greater efficacy for apremilast and that the incremental cost to achieve 1 additional PASI-75 responder by using apremilast is $187,888 annually.²¹

Psoriatic Arthritis
The PALACE clinical trials 1, 2, and 3 assessed the efficacy of apremilast in patients who had prior treatment with conventional disease-modifying antirheumatic drugs or biologics, or both. PALACE 4 evaluated efficacy in treatment-naïve patients; standard dosing of apremilast was found to produce improvement in psoriatic arthritis in treatment-naïve and non–treatment-naïve patients.^4-6,22 In the 24-week placebo-controlled phase of the PALACE 1 trial, the American College of Rheumatology (ACR) baseline composite measurement of 20% disease improvement, or ACR20, was achieved in 40% of patients randomized to the standard dosing regimen compared to 19% of patients receiving placebo, a statistically significant result (P<.001).²²

Evaluation of long-term study data is beyond the scope of this review, but those data suggest that disease outcomes continue to improve the longer therapy is utilized, with a greater percentage of patients achieving ACR20 as well as ACR50 (50% improvement) and ACR70 (70% improvement) responses. Indirect comparisons analyzing the cost and effectiveness for adalimumab, apremilast, and methotrexate in patients with psoriatic arthritis found that apremilast was less effective than adalimumab and as efficacious as methotrexate, though apremilast carries the highest price tag of these drugs.²³

Off-Label Uses

Ease of oral administration and a favorable safety profile have prompted off-label study of apremilast in other inflammatory skin diseases, including atopic dermatitis, hidradenitis suppurativa, lichen planus, rosacea, alopecia areata, and cutaneous sarcoidosis. Publications with a minimum case series of 10 patients are included in the Table.^24-32

Use in the Military and Beyond

Psoriasis and other inflammatory skin conditions are common in the military and can greatly hinder a service member’s ability to perform their duties and remain ready to deploy. A history of psoriasis is disqualifying for military recruits, but early entry into service, misdiagnosis, and low or no burden of disease at time of entry into the service all contribute to a substantial population of active-duty service members who require treatment of psoriasis.³³ Necessity dictates that treatment of this condition extend to theater operations; from 2008 to 2015, more than 3600 soldiers sought care for psoriasis while deployed to a combat theater.³⁴

In some cases, poorly controlled inflammatory skin conditions lead to medical separation.³³ Although there are limited data on the use of apremilast in the military, its use during deployment for the treatment of psoriasis and psoriatic arthritis has been reported, with the great majority of service members retaining their deployable status even 1 year after the study period.³⁵

The ideal medication for deployable military personnel should have low toxicity, simple storage, and minimal monitoring requirements, and it should not expose a service member to increased risk while in a combat theater. Worldwide deployability is a requirement for most military occupations. The risk for immunosuppression with targeted immune therapy must be fully weighed, as certain duty stations and deployments might increase the risk for exposure to Mycobacterium tuberculosis, endemic mycopathogens, hepatitis C virus, HIV, Leishmania, and Strongyloides.³⁴

Furthermore, the tumor necrosis factor α inhibitors and IL-17 and IL-23 blockers used to treat psoriasis all require refrigeration; often, this requirement cannot be met in austere overseas settings. Additional requirements for laboratory monitoring, titration of medications, and frequent office visits might prohibit a service member from performing their duties, which, in turn, is detrimental to military readiness and the career of that service member.

Last, the Centers for Disease Control and Prevention recommend avoiding live virus vaccination while taking targeted immune therapy because of safety and effectiveness concerns during immunosuppression.³⁶ This recommendation might disqualify military personnel from deployment to certain locations that require the protection that such vaccines afford. Therefore, apremilast is an ideal option for the military patient population, with many military-specific advantages.

Of course, the military is not the only population in whom ease of use and storage and simplified monitoring parameters are essential. Benefits of apremilast also may translate to patients who are placed in austere conditions or who participate in extended worldwide travel for work or leisure, such as government contractors who deploy in support of military operations, firefighters or national park employees who spend extended periods in resource-limited settings, and foreign-aid workers and diplomats who are engaged in frequent travel around the world. Furthermore, travel to certain regions might increase the risk for exposure to atypical pathogens as well as the desire for a therapeutic option that does not have potential to suppress the immune system. This subset of psoriasis patients might be better treated with novel agents such as apremilast than other drugs that would be the presumed standard of care in a domestic setting.

Final Thoughts

The benefits of apremilast translate to all patients in austere environments with limited resources and during times when immune function is of utmost concern. For military service members and many civilians in austere environments worldwide, apremilast could be considered a first-line systemic agent for psoriasis and psoriatic arthritis. In patients unable to use or tolerate other treatments, apremilast can be considered for off-label therapy (Table^24-32). There are times when the approach to prescribing must look beyond primary efficacy, AE profile, and cost—to include occupation, environment, or duties—to select the optimal medication for a patient.

Apremilast is a small-molecule biologic approved by the US Food and Drug Administration (FDA) for use in plaque psoriasis, psoriatic arthritis, and Behçet disease.^1-6 Although apremilast is seemingly a less favorable choice for treating psoriasis in the era of injectable biologics, the drug is an important option for patients in the military. In recent months, apremilast also emerged as one of a few systemic medications recommended for the treatment of psoriasis and other dermatologic conditions during the COVID-19 pandemic.⁷

In this article, we review on-label indications and off-label uses for apremilast; highlight the importance of apremilast for managing psoriasis in the military population; and propose other patient populations in whom the use of apremilast is favorable. We also present a case report that highlights and embodies the benefit of apremilast for military service members.

CASE REPORT

A 28-year-old active-duty male US Navy service member developed extensive guttate psoriasis in a distribution too wide to manage with topical medication (Figure, A–C). His condition did not improve with a trial of oral antibiotics, and he reported itch that affected his sleep. He denied new joint pain, swelling, or deformity.

A review of the patient’s service history revealed that he was serving aboard a guided-missile cruiser ship for a tour extending an additional 2 years. Limited medical resources and lack of refrigeration made the use of injectable biologics, such as adalimumab, infeasible. Furthermore, the patient was too critical to the mission to be transported frequently off the ship to a higher level of care for injection of medication. He also had trouble returning for appointments and refills because of the high operational tempo of his command.

After discussion with the patient, oral apremilast was started at 30 mg/d and titrated up to the standard dosing of 30 mg twice daily, with excellent results by 3 months after he started therapy (Figure, D–F).

COMMENT

We reviewed the research on apremilast for its approved indications, including psoriasis; its off-label uses; and strategies for using the drug to treat psoriasis and other dermatologic conditions in military populations. The most recent evidence regarding the use of apremilast in dermatology, rheumatology, and other medical specialties was assessed using published English-language research data and review articles. We conducted a PubMed search of articles indexed for MEDLINE using the following terms: apremilast, Otezla, psoriasis, psoriatic arthritis, arthritis, off-label, Behçet’s, hidradenitis suppurativa, military, and armed forces. We also reviewed citations within relevant articles to identify additional relevant sources.

Off-label uses reviewed here are based on data from randomized controlled trials, large open-label trials, and large prospective case series. Articles with less evidence are not included in this review.

On-Label Usage Profile

Apremilast is an orally administered, small-molecule inhibitor of phosphodiesterase 4. Small-molecule inhibitors are a class of medications with low molecular weight, high stability, and short half-life. They act intracellularly to modulate proinflammatory states through regulation of the proinflammatory cytokine milieu.

Apremilast has been approved by the FDA for use in adult psoriasis and psoriatic arthritis since 2014 and for use in treating oral ulcers of Behçet disease since 2019.^1-3,5,6 Recently, a phase 2, multicenter, open-label study on the use of apremilast in pediatric psoriasis patients (aged 12–17 years) demonstrated a similar safety profile with weight-based dosing⁸; phase 3 trials in this population are in the recruitment phase (ClinicalTrials.gov Identifier NCT03701763).

Because information regarding its use in pregnancy is limited, apremilast is not recommended in this population. It is unknown whether apremilast is present in breast milk; although the manufacturer does not make explicit recommendations regarding use during breastfeeding, an expert panel reviewing management of psoriasis in pregnant and breastfeeding women recommended avoiding its use while breastfeeding.⁹

Common Adverse Effects

Common adverse effects (AEs) include weight loss (>5% total body weight in 5% of patients; 5%–10% of total body weight in 10%–12% of patients; and ≥10% total body weight in 2% of patients), diarrhea and nausea, headache, and upper respiratory tract infection.^10,11 Gastrointestinal AEs tend to be self-limited and improve or resolve after the first few weeks of therapy. Caution is advised in patients older than 65 years and in those at risk for hypotension or volume depletion. Although depressed mood is a rare AE (<1%), apremilast should be used cautiously in patients with a history of depression or suicidal ideation. Weight loss generally is self-limited; routine monitoring of weight is recommended.¹¹

Apremilast in Psoriasis and Psoriatic Arthritis

Psoriasis
The ESTEEM trials established the safety and efficacy of apremilast for use in psoriasis.^2,3 In a phase 3, multicenter, double-blind, placebo-controlled trial of 844 patients, apremilast demonstrated a statistically significant 75% or greater reduction from the baseline psoriasis area and severity index score (PASI-75) in 33.1% of patients receiving the medication compared to 5.3% of those receiving placebo.² Data from real-world practice (outside constraints of clinical trials) suggest slightly greater efficacy than was demonstrated in the ESTEEM trials.

A recently published retrospective, cross-sectional study of 480 patients with psoriasis treated with apremilast reported that 48.6% of patients continuing therapy for a mean (SD) of 6 (1) months achieved PASI-75. Furthermore, the mean dermatology life quality index (DLQI) score of the surveyed population decreased from 13.4 at initiation of treatment to 5.7 at 6 (1) months of treatment—a marked improvement in quality of life.¹² Other single-center and smaller study populations also have suggested increased real-world benefit.^13,14

Nonetheless, the rate and degree of clearance of plaques with apremilast seem to lag behind what is observed with many of the biologics and traditional medications employed to treat psoriasis.^15-19 Furthermore, indirect cost analysis comparisons suggest a much higher cost per level of PASI for apremilast compared to several biologics and to methotrexate.^20,21 A study that used indirect methods of comparison to analyze the comparative cost and efficacy of apremilast and methotrexate found no evidence of greater efficacy for apremilast and that the incremental cost to achieve 1 additional PASI-75 responder by using apremilast is $187,888 annually.²¹

Psoriatic Arthritis
The PALACE clinical trials 1, 2, and 3 assessed the efficacy of apremilast in patients who had prior treatment with conventional disease-modifying antirheumatic drugs or biologics, or both. PALACE 4 evaluated efficacy in treatment-naïve patients; standard dosing of apremilast was found to produce improvement in psoriatic arthritis in treatment-naïve and non–treatment-naïve patients.^4-6,22 In the 24-week placebo-controlled phase of the PALACE 1 trial, the American College of Rheumatology (ACR) baseline composite measurement of 20% disease improvement, or ACR20, was achieved in 40% of patients randomized to the standard dosing regimen compared to 19% of patients receiving placebo, a statistically significant result (P<.001).²²

Evaluation of long-term study data is beyond the scope of this review, but those data suggest that disease outcomes continue to improve the longer therapy is utilized, with a greater percentage of patients achieving ACR20 as well as ACR50 (50% improvement) and ACR70 (70% improvement) responses. Indirect comparisons analyzing the cost and effectiveness for adalimumab, apremilast, and methotrexate in patients with psoriatic arthritis found that apremilast was less effective than adalimumab and as efficacious as methotrexate, though apremilast carries the highest price tag of these drugs.²³

Off-Label Uses

Ease of oral administration and a favorable safety profile have prompted off-label study of apremilast in other inflammatory skin diseases, including atopic dermatitis, hidradenitis suppurativa, lichen planus, rosacea, alopecia areata, and cutaneous sarcoidosis. Publications with a minimum case series of 10 patients are included in the Table.^24-32

Use in the Military and Beyond

Psoriasis and other inflammatory skin conditions are common in the military and can greatly hinder a service member’s ability to perform their duties and remain ready to deploy. A history of psoriasis is disqualifying for military recruits, but early entry into service, misdiagnosis, and low or no burden of disease at time of entry into the service all contribute to a substantial population of active-duty service members who require treatment of psoriasis.³³ Necessity dictates that treatment of this condition extend to theater operations; from 2008 to 2015, more than 3600 soldiers sought care for psoriasis while deployed to a combat theater.³⁴

In some cases, poorly controlled inflammatory skin conditions lead to medical separation.³³ Although there are limited data on the use of apremilast in the military, its use during deployment for the treatment of psoriasis and psoriatic arthritis has been reported, with the great majority of service members retaining their deployable status even 1 year after the study period.³⁵

The ideal medication for deployable military personnel should have low toxicity, simple storage, and minimal monitoring requirements, and it should not expose a service member to increased risk while in a combat theater. Worldwide deployability is a requirement for most military occupations. The risk for immunosuppression with targeted immune therapy must be fully weighed, as certain duty stations and deployments might increase the risk for exposure to Mycobacterium tuberculosis, endemic mycopathogens, hepatitis C virus, HIV, Leishmania, and Strongyloides.³⁴

Furthermore, the tumor necrosis factor α inhibitors and IL-17 and IL-23 blockers used to treat psoriasis all require refrigeration; often, this requirement cannot be met in austere overseas settings. Additional requirements for laboratory monitoring, titration of medications, and frequent office visits might prohibit a service member from performing their duties, which, in turn, is detrimental to military readiness and the career of that service member.

Last, the Centers for Disease Control and Prevention recommend avoiding live virus vaccination while taking targeted immune therapy because of safety and effectiveness concerns during immunosuppression.³⁶ This recommendation might disqualify military personnel from deployment to certain locations that require the protection that such vaccines afford. Therefore, apremilast is an ideal option for the military patient population, with many military-specific advantages.

Of course, the military is not the only population in whom ease of use and storage and simplified monitoring parameters are essential. Benefits of apremilast also may translate to patients who are placed in austere conditions or who participate in extended worldwide travel for work or leisure, such as government contractors who deploy in support of military operations, firefighters or national park employees who spend extended periods in resource-limited settings, and foreign-aid workers and diplomats who are engaged in frequent travel around the world. Furthermore, travel to certain regions might increase the risk for exposure to atypical pathogens as well as the desire for a therapeutic option that does not have potential to suppress the immune system. This subset of psoriasis patients might be better treated with novel agents such as apremilast than other drugs that would be the presumed standard of care in a domestic setting.

Final Thoughts

The benefits of apremilast translate to all patients in austere environments with limited resources and during times when immune function is of utmost concern. For military service members and many civilians in austere environments worldwide, apremilast could be considered a first-line systemic agent for psoriasis and psoriatic arthritis. In patients unable to use or tolerate other treatments, apremilast can be considered for off-label therapy (Table^24-32). There are times when the approach to prescribing must look beyond primary efficacy, AE profile, and cost—to include occupation, environment, or duties—to select the optimal medication for a patient.

The virus that causes COVID-19—SARS-CoV-2—has infected more than 128 million individuals, resulting in more than 2.8 million deaths worldwide between December 2019 and April 2021. Disease mortality primarily is driven by hypoxemic respiratory failure and systemic hypercoagulability, resulting in multisystem organ failure.¹ With more than 17 million Americans infected, the virus is estimated to have impacted someone within the social circle of nearly every American.²

The COVID-19 pandemic has highlighted resource limitations, delayed elective and preventive care, and rapidly increased the adoption of telemedicine, presenting a host of new challenges to providers in every medical specialty, including dermatology. Although COVID-19 primarily is a respiratory disease, clinical manifestations have been observed in nearly every organ, including the skin. The cutaneous manifestations of COVID-19 provide insight into disease diagnosis, prognosis, and pathophysiology. In this article, we review the cutaneous manifestations of COVID-19 and explore the state of knowledge regarding their pathophysiology and clinical significance. Finally, we discuss the role of dermatology consultants in the care of patients with COVID-19, and the impact of the pandemic on the field of dermatology. 

Prevalence of Cutaneous Findings in COVID-19

Early reports characterizing the clinical presentation of patients hospitalized with COVID-19 suggested skin findings associated with the disease were rare. Cohort studies from Europe, China, and New York City in January through March 2020 reported a low prevalence or made no mention of rash.^3-7 However, reports from dermatologists in Italy that emerged in May 2020 indicated a substantially higher proportion of cutaneous disease: 18 of 88 (20.4%) hospitalized patients were found to have cutaneous involvement, primarily consisting of erythematous rash, along with some cases of urticarial and vesicular lesions.⁸ In October 2020, a retrospective cohort study from Spain examining 2761 patients presenting to the emergency department or admitted to the hospital for COVID-19 found that 58 (2.1%) patients had skin lesions attributed to COVID-19.⁹

The wide range in reported prevalence of skin lesions may be due to variable involvement of dermatologic specialists in patient care, particularly in China.¹⁰ Some variation also may be due to variability in the timing of clinical examination, as well as demographic and clinical differences in patient populations. Of note, a multisystem inflammatory disease seen in US children subsequent to infection with COVID-19 has been associated with rash in as many as 74% of cases.¹¹ Although COVID-19 disproportionately impacts people with skin of color, there are few reports of cutaneous manifestations in that population,¹² highlighting the challenges of the dermatologic examination in individuals with darker skin and suggesting the prevalence of dermatologic disease in COVID-19 may be greater than reported. 

Morphologic Patterns of Cutaneous Involvement in COVID-19

Researchers in Europe and the United States have attempted to classify the cutaneous manifestations of COVID-19. A registry established through the American Academy of Dermatology published a compilation of reports from 31 countries, totaling 716 patient profiles.¹³ A prospective Spanish study detailed the cutaneous involvement of 375 patients with suspected or confirmed COVID-19.¹⁴ Together, these efforts have revealed several distinct patterns of cutaneous involvement associated with COVID-19 (Table).^9,15-18 

Vesicular Rash
Vesicular rash associated with COVID-19 has been described in several studies and case series^8,13,14 and is considered, along with the pseudopernio (or pseudochilblains) morphology, to be one of the more disease-specific patterns in COVID-19.^14,18 Vesicular rash appears to comprise roughly one-tenth of all COVID-19–associated rashes.^13,14 It usually is described as pruritic, with 72% to 83% of patients reporting itch.^13,16 

Small monomorphic or polymorphic vesicles predominantly on the trunk and to a lesser extent the extremities and head have been described by multiple authors.^14,16 Vesicular rash is most common among middle-aged individuals, with studies reporting median and mean ages ranging from 40.5 to 55 years.^9,13,14,16

Vesicular rash develops concurrent with or after other presenting symptoms of COVID-19; in 2 studies, vesicular rash preceded development of other symptoms in only 15% and 5.6% of cases, respectively.^13,14 Prognostically, vesicular rash is associated with moderate disease severity.^14,16 It may persist for an average of 8 to 10 days.^14,16,18

Histopathologic examination reveals basal layer vacuolar degeneration, hyperchromatic keratinocytes, acantholysis, and dyskeratosis.^9,16,18 

Urticarial Rash
Urticarial lesions represent approximately 7% to 19% of reported COVID-19–associated rashes.^9,13,14 Urticarial rashes in patients testing positive for SARS-CoV-2 primarily occur on the trunk.¹⁴ The urticaria, which typically last about 1 week,¹⁴ are seen most frequently in middle-aged patients (mean/median age, 42–48 years)^13,14 and are associated with pruritus, which has been reported in 74% to 92% of patients.^13,14 Urticarial lesions typically do not precede other symptoms of COVID-19 and are nonspecific, making them less useful diagnostically.¹⁴

Urticaria appears to be associated with more severe COVID-19 illness in several studies, but this finding may be confounded by several factors, including older age, increased tobacco use, and polypharmacy. Of 104 patients with reported urticarial rash and suspected or confirmed COVID-19 across 3 studies, only 1 death was reported.^9,13,14 

The histopathologic appearance is that of typical hives, demonstrating a perivascular infiltrate of lymphocytes and eosinophils with edema of the upper dermis.^9,19

Morbilliform Eruption
Morbilliform eruption is a commonly reported morphology associated with COVID-19, accounting for 20% to 47% of rashes.^9,13,14 This categorization may have limited utility from a diagnostic and prognostic perspective, given that morbilliform eruptions are common, nonspecific, and heterogenous and can arise from many causes.^9,13,14 Onset of morbilliform eruption appears to coincide with¹⁴ or follow^13,20,21 the development of other COVID-19–related symptoms, with 5% of patients reporting morbilliform rash as the initial manifestation of infection.^13,14 Morbilliform eruptions have been observed to occur in patients with more severe disease.^9,13,14

Certain morphologic subtypes, such as erythema multiforme–like, erythema elevatum diutinum–like, or pseudovesicular, may be more specific to COVID-19 infection.¹⁴ A small case series highlighted 4 patients with erythema multiforme–like eruptions, 3 of whom also were found to have petechial enanthem occurring after COVID-19 diagnosis; however, the investigators were unable to exclude drug reaction as a potential cause of rash in these patients.²² Another case series of 21 patients with COVID-19 and skin rash described a (primarily) petechial enanthem on the palate in 6 (28.5%) patients.²³ It is unclear to what extent oral enanthem may be underrecognized given that some physicians may be disinclined to remove the masks of known COVID-19–positive patients to examine the oral cavity.

The histologic appearance of morbilliform rash seen in association with COVID-19 has been described as spongiotic with interface dermatitis with perivascular lymphocytic inflammation.^9,21

COVID Toes, Pseudochilblains Rash, Perniolike Rash, and Acral Erythema/Edema
Of all the rashes associated with COVID-19, COVID toes, or pseudochilblains rash, has perhaps attracted the most attention. The characteristic violaceous erythema on the fingers and/or toes may be itchy or painful, presenting similar to idiopathic cases of pernio (Figure 1).¹⁴ The entity has been controversial because of an absence of a clear correlation with a positive SARS-CoV-2 polymerase chain reaction test or antibodies to the virus in a subset of reported cases.^24,25 Onset of the rash late in the disease course, generally after symptom resolution in mild or asymptomatic cases, may explain the absence of viral DNA in the nasopharynx by the time of lesion appearance.^14,26 Seronegative patients may have cleared SARS-CoV-2 infection before humoral immunity could occur via a strong type 1 interferon response.²⁵

Across 3 studies, perniolike skin lesions constituted 18% to 29% of COVID-19–associated skin findings^9,13,14 and persisted for an average of 12 to 14 days.^13,14 Perniolike lesions portend a favorable outcome; patients with COVID toes rarely present with systemic symptoms or laboratory or imaging abnormalities⁹ and less commonly require hospitalization for severe illness. Perniolike lesions have been reported most frequently in younger patients, with a median or mean age of 32 to 35 years.^13,14

Histology demonstrates lichenoid dermatitis with perivascular and periadnexal lymphocytic infiltrates.⁹ Notably, one study observed interface dermatitis of the intraepidermal portion of the acrosyringium, a rare finding in chilblain lupus, in 83% of patients (N=40).²⁵ Direct immunofluorescence demonstrates a vasculopathic pattern, with some patients showing deposition of IgM or IgG, C3, and fibrinogen in dermal blood vessels. Vascular C9 deposits also have been demonstrated on immunohistochemistry.⁹ Biopsies of perniolike lesions in COVID-19 patients have demonstrated the presence of SARS-CoV-2 RNA,²⁷ have identified SARS-CoV-2 spike protein in endothelial cells on immunohistochemistry, and have visualized intracytoplasmic viral particles in vascular endothelium on electron microscopy.²⁸

Livedoid Rash/Retiform Purpura
Netlike purpuric or violaceous patches signifying vessel damage or occlusion have been seen in association with COVID-19, constituting approximately 6% of COVID-19–associated skin findings in 2 studies.^13,14 Livedoid rash (Figure 2) and retiform purpura (Figure 3) are associated with older age and occur primarily in severely ill patients, including those requiring intensive care. In a registry of 716 patients with COVID-19, 100% of patients with retiform purpura were hospitalized, and 82% had acute respiratory distress syndrome.¹³ In another study, 33% (7/21) of patients with livedoid and necrotic lesions required intensive care, and 10% (2/21) died.¹⁴

Multisystem Inflammatory Disease in Children

A hyperinflammatory syndrome similar to Kawasaki disease and toxic shock syndrome associated with mucocutaneous, cardiac, and gastrointestinal manifestations has been reported following COVID-19 infection.³¹ This syndrome, known as multisystem inflammatory syndrome in children (MIS-C), predominantly affects adolescents and children older than 5 years,¹¹ typically occurs 2 to 4 weeks after infection, and appears to be at least 100-times less common than COVID-19 infection among the same age group.³¹ Sixty percent³¹ to 74%¹¹ of affected patients have mucocutaneous involvement, with the most common clinical findings being conjunctival injection, palmoplantar erythema, lip hyperemia, periorbital erythema and edema, strawberry tongue, and malar erythema, respectively.³²

Because this condition appears to reflect an immune response to the virus, the majority of cases demonstrate negative SARS-CoV-2 polymerase chain reaction and positive antibody testing.³³ Although cutaneous findings are similar to those seen in Kawasaki disease, certain findings have been noted in MIS-C that are not typical of Kawasaki disease, including heliotrope rash–like periorbital edema and erythema as well as erythema infectiosum–like malar erythema and reticulated erythematous eruptions.³²

The course of MIS-C can be severe; in one case series of patients presenting with MIS-C, 80% (79/99) required intensive care unit admission, with 10% requiring mechanical ventilation and 2% of patients dying during admission.³¹ Cardiac dysfunction, coagulopathy, and gastrointestinal symptoms are common.^11,31 It has been postulated that a superantigenlike region of the SARS-CoV-2 spike protein, similar to that of staphylococcal enterotoxin B, may underlie MIS-C and account for its similarities to toxic shock syndrome.³⁴ Of note, a similar multisystem inflammatory syndrome associated with COVID-19 also has been described in adults, and it too may present with rash as a cardinal feature.³⁵

Pathophysiology of COVID-19: What the Skin May Reveal About the Disease

The diverse range of cutaneous manifestations in COVID-19 reflects a spectrum of host immunologicresponses to SARS-CoV-2 and may inform the pathophysiology of the disease as well as potential treatment modalities.

Host Response to SARS-CoV-2
The body’s response to viral infection is 2-pronged, involving activation of cellular antiviral defenses mediated by type I and III interferons, as well as recruitment of leukocytes, mobilized by cytokines and chemokines.^36,37 Infection with SARS-CoV-2 results in a unique inflammatory response characterized by suppression of interferons, juxtaposed with a rampant proinflammatory cytokine and chemokine response, reminiscent of a cytokine storm. Reflective of this imbalance, a study of 50 COVID-19 patients and 20 healthy controls found decreased natural killer cells and CD3⁺ T cells in COVID-19 patients, particularly severely or critically ill patients, with an increase in B cells and monocytes.³⁸ This distinctive immune imbalance positions SARS-CoV-2 to thrive in the absence of inhibitory interferon activity while submitting the host to the deleterious effects of a cytokine surge.³⁶

Type I Interferons
The perniolike lesions associated with mild COVID-19 disease¹⁴ may represent a robust immune response via effective stimulation of type I interferons (IFN-1). Similar perniolike lesions are observed in Aicardi-Goutières syndrome³⁷ and familial chilblain lupus, hereditary interferonopathies associated with mutations in the TREX1 (three prime repair exonuclease 1) gene and characterized by inappropriate upregulation of IFN-1,³⁹ resulting in chilblains. It has been suggested that perniolike lesions in COVID-19 result from IFN-1 activation—a robust effective immunologic response to the virus.^14,26,40

On the other end of the spectrum, patients with severe COVID-19 may have a blunted IFN-1 response and reduced IFN-1–stimulated gene expression.^36,38 Notably, low IFN-1 response preceded clinical deterioration and was associated with increased risk for evolution to critical illness.³⁸ Severe disease from COVID-19 also is more commonly observed in older patients and those with comorbidities,¹ both of which are known factors associated with depressed IFN-1 function.^38,41 Reflective of this disparate IFN-1 response, biopsies of COVID-19 perniosis have demonstrated striking expression of myxovirus resistance protein A (MXA), a marker for IFN-1 signaling in tissue, whereas its expression is absent in COVID-19 livedo/retiform purpura.²⁷

Familial chilblain lupus may be effectively treated by the Janus kinase inhibitor baricitinib,³⁹ which inhibits IFN-1 signaling. Baricitinib recently received emergency use authorization by the US Food and Drug Administration for treatment of severe COVID-19 pneumonia,^42,43 hinting to disordered IFN-1 signaling in the COVID-19 pathophysiology.

The impaired IFN-1 response in COVID-19 patients may be due to a unique characteristic of SARS-CoV-2: its ORF3b gene is a potent IFN-1 antagonist. In a series of experiments comparing SARS-CoV-2 to the related virus severe acute respiratory disease coronavirus (which was responsible for an epidemic in 2002), Konno et al⁴⁴ found that SARS-CoV-2 is more effectively able to downregulate host IFN-1, likely due to premature stop codons on ORF3b that produce a truncated version of the gene with amplified anti–IFN-1 activity.

 Cytokine Storm and Coagulation Cascade
This dulled interferon response is juxtaposed with a surge of inflammatory chemokines and cytokines, including IL-6, IL-8, IL-10, and tumor necrosis factor α, impairing innate immunity and leading to end-organ damage. This inflammatory response is associated with the influx of innate immune cells, specifically neutrophils and monocytes, which likely contribute to lung injury in COVID-19 acute respiratory distress syndrome.³⁸ It also is thought to lead to downstream activation of coagulation, with a high incidence of thrombotic events observed in patients with severe COVID-19.¹ In a retrospective study of 184 intensive care patients with COVID-19 receiving at least standard doses of thromboprophylaxis, venous thromboembolism occurred in 27% and arterial thrombotic events occurred in 3.7%.⁴⁵

Livedo racemosa and retiform purpura are cutaneous markers of hypercoagulability, which indicate an increased risk for systemic clotting in COVID-19. A positive feedback loop between the complement and coagulation cascades appears to be important.^{13,14,29,46-48} In addition, a few studies have reported antiphospholipid antibody positivity in hospitalized COVID-19 patients.^49,50

The high incidence of coagulopathy in severe COVID-19 has prompted many institutions to develop aggressive prophylactic anticoagulation protocols. Elevation of proinflammatory cytokines and observation of terminal complement activation in the skin and other organs has led to therapeutic trials of IL-6 inhibitors such as tocilizumab,⁵¹ complement inhibitors such as eculizumab, and Janus kinase inhibitors such as ruxolitinib and baricitinib.^42,48

COVID Long-Haulers
The long-term effects of immune dysregulation in COVID-19 patients remain to be seen. Viral triggering of autoimmune disease is a well-established phenomenon, seen in DRESS (drug reaction with eosinophilia and systemic symptoms) syndrome and other dermatologic diseases, raising the possibility that dermatologists will see a rising incidence of cutaneous autoimmune disease in the aftermath of the pandemic. Disordered interferon stimulation could lead to increased incidence of interferon-mediated disorders, such as sarcoidosis and other granulomatous diseases. Vasculitislike skin lesions could persist beyond the acute infectious period. Recent data from a registry of 990 COVID-19 cases from 39 countries suggest that COVID-19 perniolike lesions may persist as long as 150 days.⁵² In a time of many unknowns, these questions serve as a call to action for rigorous data collection, contribution to existing registries for dermatologic manifestations of COVID-19, and long-term follow-up of COVID-19 patients by the dermatology community. 

Pandemic Dermatology

The pandemic has posed unprecedented challenges for patient care. The use of hydroxychloroquine as a popular but unproven treatment for COVID-19, ⁵³ particularly early in the pandemic, has resulted in drug shortages for patients with lupus and other autoimmune skin diseases. Meanwhile, the need for patients with complex dermatologic conditions to receive systemic immunosuppression has had to be balanced against the associated risks during a global pandemic. To help dermatologists navigate this dilemma, various subspecialty groups have issued guidelines, including the COVID-19 Task Force of the Medical Dermatology Society and Society of Dermatology Hospitalists, which recommends a stepwise approach to shared decision-making with the goal of minimizing both the risk for disease flare and that of infection. The use of systemic steroids and rituximab, as well as the dose of immunosuppression—particularly broad-acting immunosuppression—should be limited where permitted. ⁵⁴

Rapid adoption of telemedicine and remote monitoring strategies has enabled dermatologists to provide safe and timely care when in-person visits have not been possible, including for patients with confirmed or suspected COVID-19, as well as for hospitalized patients. ^55-57 Use of telemedicine has facilitated preservation of personal protective equipment at a time when these important resources have been scarce. For patients with transportation or scheduling barriers, telemedicine has even expanded access to care. 

However, this strategy cannot completely replace comprehensive in-person evaluation. Variability in video and photographic quality limits evaluation, while in-person physical examination can reveal subtle morphologic clues necessary for diagnosis. ^{5 8} Additionally, unequal access to technology may disadvantage some patients. For dermatologists to provide optimal care and continue to contribute accurate and insightful observations into COVID-19, it is essential to be physically present in the clinic and in the hospital when necessary, caring for patients in need of dermatologic expertise. Creative management strategies developed during this time will benefit patients and expand the reach of the specialty . ^{5 8}

Final Thoughts

The COVID-19 pandemic has profoundly challenged the medical community and dermatology is no exception. By documenting and characterizing the diverse cutaneous manifestations of this novel disease, dermatologists have furthered understanding of its pathophysiology and management. By adapting quickly and developing creative ways to deliver care, dermatologists have found ways to contribute, both large and small. As we take stock at this juncture of the pandemic, it is clear there remains much to learn. We hope dermatologists will continue to take an active role in meeting the challenges of this time.

The virus that causes COVID-19—SARS-CoV-2—has infected more than 128 million individuals, resulting in more than 2.8 million deaths worldwide between December 2019 and April 2021. Disease mortality primarily is driven by hypoxemic respiratory failure and systemic hypercoagulability, resulting in multisystem organ failure.¹ With more than 17 million Americans infected, the virus is estimated to have impacted someone within the social circle of nearly every American.²

The COVID-19 pandemic has highlighted resource limitations, delayed elective and preventive care, and rapidly increased the adoption of telemedicine, presenting a host of new challenges to providers in every medical specialty, including dermatology. Although COVID-19 primarily is a respiratory disease, clinical manifestations have been observed in nearly every organ, including the skin. The cutaneous manifestations of COVID-19 provide insight into disease diagnosis, prognosis, and pathophysiology. In this article, we review the cutaneous manifestations of COVID-19 and explore the state of knowledge regarding their pathophysiology and clinical significance. Finally, we discuss the role of dermatology consultants in the care of patients with COVID-19, and the impact of the pandemic on the field of dermatology. 

Prevalence of Cutaneous Findings in COVID-19

Early reports characterizing the clinical presentation of patients hospitalized with COVID-19 suggested skin findings associated with the disease were rare. Cohort studies from Europe, China, and New York City in January through March 2020 reported a low prevalence or made no mention of rash.^3-7 However, reports from dermatologists in Italy that emerged in May 2020 indicated a substantially higher proportion of cutaneous disease: 18 of 88 (20.4%) hospitalized patients were found to have cutaneous involvement, primarily consisting of erythematous rash, along with some cases of urticarial and vesicular lesions.⁸ In October 2020, a retrospective cohort study from Spain examining 2761 patients presenting to the emergency department or admitted to the hospital for COVID-19 found that 58 (2.1%) patients had skin lesions attributed to COVID-19.⁹

The wide range in reported prevalence of skin lesions may be due to variable involvement of dermatologic specialists in patient care, particularly in China.¹⁰ Some variation also may be due to variability in the timing of clinical examination, as well as demographic and clinical differences in patient populations. Of note, a multisystem inflammatory disease seen in US children subsequent to infection with COVID-19 has been associated with rash in as many as 74% of cases.¹¹ Although COVID-19 disproportionately impacts people with skin of color, there are few reports of cutaneous manifestations in that population,¹² highlighting the challenges of the dermatologic examination in individuals with darker skin and suggesting the prevalence of dermatologic disease in COVID-19 may be greater than reported. 

Morphologic Patterns of Cutaneous Involvement in COVID-19

Researchers in Europe and the United States have attempted to classify the cutaneous manifestations of COVID-19. A registry established through the American Academy of Dermatology published a compilation of reports from 31 countries, totaling 716 patient profiles.¹³ A prospective Spanish study detailed the cutaneous involvement of 375 patients with suspected or confirmed COVID-19.¹⁴ Together, these efforts have revealed several distinct patterns of cutaneous involvement associated with COVID-19 (Table).^9,15-18 

Vesicular Rash
Vesicular rash associated with COVID-19 has been described in several studies and case series^8,13,14 and is considered, along with the pseudopernio (or pseudochilblains) morphology, to be one of the more disease-specific patterns in COVID-19.^14,18 Vesicular rash appears to comprise roughly one-tenth of all COVID-19–associated rashes.^13,14 It usually is described as pruritic, with 72% to 83% of patients reporting itch.^13,16 

Small monomorphic or polymorphic vesicles predominantly on the trunk and to a lesser extent the extremities and head have been described by multiple authors.^14,16 Vesicular rash is most common among middle-aged individuals, with studies reporting median and mean ages ranging from 40.5 to 55 years.^9,13,14,16

Vesicular rash develops concurrent with or after other presenting symptoms of COVID-19; in 2 studies, vesicular rash preceded development of other symptoms in only 15% and 5.6% of cases, respectively.^13,14 Prognostically, vesicular rash is associated with moderate disease severity.^14,16 It may persist for an average of 8 to 10 days.^14,16,18

Histopathologic examination reveals basal layer vacuolar degeneration, hyperchromatic keratinocytes, acantholysis, and dyskeratosis.^9,16,18 

Urticarial Rash
Urticarial lesions represent approximately 7% to 19% of reported COVID-19–associated rashes.^9,13,14 Urticarial rashes in patients testing positive for SARS-CoV-2 primarily occur on the trunk.¹⁴ The urticaria, which typically last about 1 week,¹⁴ are seen most frequently in middle-aged patients (mean/median age, 42–48 years)^13,14 and are associated with pruritus, which has been reported in 74% to 92% of patients.^13,14 Urticarial lesions typically do not precede other symptoms of COVID-19 and are nonspecific, making them less useful diagnostically.¹⁴

Urticaria appears to be associated with more severe COVID-19 illness in several studies, but this finding may be confounded by several factors, including older age, increased tobacco use, and polypharmacy. Of 104 patients with reported urticarial rash and suspected or confirmed COVID-19 across 3 studies, only 1 death was reported.^9,13,14 

The histopathologic appearance is that of typical hives, demonstrating a perivascular infiltrate of lymphocytes and eosinophils with edema of the upper dermis.^9,19

Morbilliform Eruption
Morbilliform eruption is a commonly reported morphology associated with COVID-19, accounting for 20% to 47% of rashes.^9,13,14 This categorization may have limited utility from a diagnostic and prognostic perspective, given that morbilliform eruptions are common, nonspecific, and heterogenous and can arise from many causes.^9,13,14 Onset of morbilliform eruption appears to coincide with¹⁴ or follow^13,20,21 the development of other COVID-19–related symptoms, with 5% of patients reporting morbilliform rash as the initial manifestation of infection.^13,14 Morbilliform eruptions have been observed to occur in patients with more severe disease.^9,13,14

Certain morphologic subtypes, such as erythema multiforme–like, erythema elevatum diutinum–like, or pseudovesicular, may be more specific to COVID-19 infection.¹⁴ A small case series highlighted 4 patients with erythema multiforme–like eruptions, 3 of whom also were found to have petechial enanthem occurring after COVID-19 diagnosis; however, the investigators were unable to exclude drug reaction as a potential cause of rash in these patients.²² Another case series of 21 patients with COVID-19 and skin rash described a (primarily) petechial enanthem on the palate in 6 (28.5%) patients.²³ It is unclear to what extent oral enanthem may be underrecognized given that some physicians may be disinclined to remove the masks of known COVID-19–positive patients to examine the oral cavity.

The histologic appearance of morbilliform rash seen in association with COVID-19 has been described as spongiotic with interface dermatitis with perivascular lymphocytic inflammation.^9,21

COVID Toes, Pseudochilblains Rash, Perniolike Rash, and Acral Erythema/Edema
Of all the rashes associated with COVID-19, COVID toes, or pseudochilblains rash, has perhaps attracted the most attention. The characteristic violaceous erythema on the fingers and/or toes may be itchy or painful, presenting similar to idiopathic cases of pernio (Figure 1).¹⁴ The entity has been controversial because of an absence of a clear correlation with a positive SARS-CoV-2 polymerase chain reaction test or antibodies to the virus in a subset of reported cases.^24,25 Onset of the rash late in the disease course, generally after symptom resolution in mild or asymptomatic cases, may explain the absence of viral DNA in the nasopharynx by the time of lesion appearance.^14,26 Seronegative patients may have cleared SARS-CoV-2 infection before humoral immunity could occur via a strong type 1 interferon response.²⁵

Across 3 studies, perniolike skin lesions constituted 18% to 29% of COVID-19–associated skin findings^9,13,14 and persisted for an average of 12 to 14 days.^13,14 Perniolike lesions portend a favorable outcome; patients with COVID toes rarely present with systemic symptoms or laboratory or imaging abnormalities⁹ and less commonly require hospitalization for severe illness. Perniolike lesions have been reported most frequently in younger patients, with a median or mean age of 32 to 35 years.^13,14

Histology demonstrates lichenoid dermatitis with perivascular and periadnexal lymphocytic infiltrates.⁹ Notably, one study observed interface dermatitis of the intraepidermal portion of the acrosyringium, a rare finding in chilblain lupus, in 83% of patients (N=40).²⁵ Direct immunofluorescence demonstrates a vasculopathic pattern, with some patients showing deposition of IgM or IgG, C3, and fibrinogen in dermal blood vessels. Vascular C9 deposits also have been demonstrated on immunohistochemistry.⁹ Biopsies of perniolike lesions in COVID-19 patients have demonstrated the presence of SARS-CoV-2 RNA,²⁷ have identified SARS-CoV-2 spike protein in endothelial cells on immunohistochemistry, and have visualized intracytoplasmic viral particles in vascular endothelium on electron microscopy.²⁸

Livedoid Rash/Retiform Purpura
Netlike purpuric or violaceous patches signifying vessel damage or occlusion have been seen in association with COVID-19, constituting approximately 6% of COVID-19–associated skin findings in 2 studies.^13,14 Livedoid rash (Figure 2) and retiform purpura (Figure 3) are associated with older age and occur primarily in severely ill patients, including those requiring intensive care. In a registry of 716 patients with COVID-19, 100% of patients with retiform purpura were hospitalized, and 82% had acute respiratory distress syndrome.¹³ In another study, 33% (7/21) of patients with livedoid and necrotic lesions required intensive care, and 10% (2/21) died.¹⁴

Multisystem Inflammatory Disease in Children

A hyperinflammatory syndrome similar to Kawasaki disease and toxic shock syndrome associated with mucocutaneous, cardiac, and gastrointestinal manifestations has been reported following COVID-19 infection.³¹ This syndrome, known as multisystem inflammatory syndrome in children (MIS-C), predominantly affects adolescents and children older than 5 years,¹¹ typically occurs 2 to 4 weeks after infection, and appears to be at least 100-times less common than COVID-19 infection among the same age group.³¹ Sixty percent³¹ to 74%¹¹ of affected patients have mucocutaneous involvement, with the most common clinical findings being conjunctival injection, palmoplantar erythema, lip hyperemia, periorbital erythema and edema, strawberry tongue, and malar erythema, respectively.³²

Because this condition appears to reflect an immune response to the virus, the majority of cases demonstrate negative SARS-CoV-2 polymerase chain reaction and positive antibody testing.³³ Although cutaneous findings are similar to those seen in Kawasaki disease, certain findings have been noted in MIS-C that are not typical of Kawasaki disease, including heliotrope rash–like periorbital edema and erythema as well as erythema infectiosum–like malar erythema and reticulated erythematous eruptions.³²

The course of MIS-C can be severe; in one case series of patients presenting with MIS-C, 80% (79/99) required intensive care unit admission, with 10% requiring mechanical ventilation and 2% of patients dying during admission.³¹ Cardiac dysfunction, coagulopathy, and gastrointestinal symptoms are common.^11,31 It has been postulated that a superantigenlike region of the SARS-CoV-2 spike protein, similar to that of staphylococcal enterotoxin B, may underlie MIS-C and account for its similarities to toxic shock syndrome.³⁴ Of note, a similar multisystem inflammatory syndrome associated with COVID-19 also has been described in adults, and it too may present with rash as a cardinal feature.³⁵

Pathophysiology of COVID-19: What the Skin May Reveal About the Disease

The diverse range of cutaneous manifestations in COVID-19 reflects a spectrum of host immunologicresponses to SARS-CoV-2 and may inform the pathophysiology of the disease as well as potential treatment modalities.

Host Response to SARS-CoV-2
The body’s response to viral infection is 2-pronged, involving activation of cellular antiviral defenses mediated by type I and III interferons, as well as recruitment of leukocytes, mobilized by cytokines and chemokines.^36,37 Infection with SARS-CoV-2 results in a unique inflammatory response characterized by suppression of interferons, juxtaposed with a rampant proinflammatory cytokine and chemokine response, reminiscent of a cytokine storm. Reflective of this imbalance, a study of 50 COVID-19 patients and 20 healthy controls found decreased natural killer cells and CD3⁺ T cells in COVID-19 patients, particularly severely or critically ill patients, with an increase in B cells and monocytes.³⁸ This distinctive immune imbalance positions SARS-CoV-2 to thrive in the absence of inhibitory interferon activity while submitting the host to the deleterious effects of a cytokine surge.³⁶

Type I Interferons
The perniolike lesions associated with mild COVID-19 disease¹⁴ may represent a robust immune response via effective stimulation of type I interferons (IFN-1). Similar perniolike lesions are observed in Aicardi-Goutières syndrome³⁷ and familial chilblain lupus, hereditary interferonopathies associated with mutations in the TREX1 (three prime repair exonuclease 1) gene and characterized by inappropriate upregulation of IFN-1,³⁹ resulting in chilblains. It has been suggested that perniolike lesions in COVID-19 result from IFN-1 activation—a robust effective immunologic response to the virus.^14,26,40

On the other end of the spectrum, patients with severe COVID-19 may have a blunted IFN-1 response and reduced IFN-1–stimulated gene expression.^36,38 Notably, low IFN-1 response preceded clinical deterioration and was associated with increased risk for evolution to critical illness.³⁸ Severe disease from COVID-19 also is more commonly observed in older patients and those with comorbidities,¹ both of which are known factors associated with depressed IFN-1 function.^38,41 Reflective of this disparate IFN-1 response, biopsies of COVID-19 perniosis have demonstrated striking expression of myxovirus resistance protein A (MXA), a marker for IFN-1 signaling in tissue, whereas its expression is absent in COVID-19 livedo/retiform purpura.²⁷

Familial chilblain lupus may be effectively treated by the Janus kinase inhibitor baricitinib,³⁹ which inhibits IFN-1 signaling. Baricitinib recently received emergency use authorization by the US Food and Drug Administration for treatment of severe COVID-19 pneumonia,^42,43 hinting to disordered IFN-1 signaling in the COVID-19 pathophysiology.

The impaired IFN-1 response in COVID-19 patients may be due to a unique characteristic of SARS-CoV-2: its ORF3b gene is a potent IFN-1 antagonist. In a series of experiments comparing SARS-CoV-2 to the related virus severe acute respiratory disease coronavirus (which was responsible for an epidemic in 2002), Konno et al⁴⁴ found that SARS-CoV-2 is more effectively able to downregulate host IFN-1, likely due to premature stop codons on ORF3b that produce a truncated version of the gene with amplified anti–IFN-1 activity.

 Cytokine Storm and Coagulation Cascade
This dulled interferon response is juxtaposed with a surge of inflammatory chemokines and cytokines, including IL-6, IL-8, IL-10, and tumor necrosis factor α, impairing innate immunity and leading to end-organ damage. This inflammatory response is associated with the influx of innate immune cells, specifically neutrophils and monocytes, which likely contribute to lung injury in COVID-19 acute respiratory distress syndrome.³⁸ It also is thought to lead to downstream activation of coagulation, with a high incidence of thrombotic events observed in patients with severe COVID-19.¹ In a retrospective study of 184 intensive care patients with COVID-19 receiving at least standard doses of thromboprophylaxis, venous thromboembolism occurred in 27% and arterial thrombotic events occurred in 3.7%.⁴⁵

Livedo racemosa and retiform purpura are cutaneous markers of hypercoagulability, which indicate an increased risk for systemic clotting in COVID-19. A positive feedback loop between the complement and coagulation cascades appears to be important.^{13,14,29,46-48} In addition, a few studies have reported antiphospholipid antibody positivity in hospitalized COVID-19 patients.^49,50

The high incidence of coagulopathy in severe COVID-19 has prompted many institutions to develop aggressive prophylactic anticoagulation protocols. Elevation of proinflammatory cytokines and observation of terminal complement activation in the skin and other organs has led to therapeutic trials of IL-6 inhibitors such as tocilizumab,⁵¹ complement inhibitors such as eculizumab, and Janus kinase inhibitors such as ruxolitinib and baricitinib.^42,48

COVID Long-Haulers
The long-term effects of immune dysregulation in COVID-19 patients remain to be seen. Viral triggering of autoimmune disease is a well-established phenomenon, seen in DRESS (drug reaction with eosinophilia and systemic symptoms) syndrome and other dermatologic diseases, raising the possibility that dermatologists will see a rising incidence of cutaneous autoimmune disease in the aftermath of the pandemic. Disordered interferon stimulation could lead to increased incidence of interferon-mediated disorders, such as sarcoidosis and other granulomatous diseases. Vasculitislike skin lesions could persist beyond the acute infectious period. Recent data from a registry of 990 COVID-19 cases from 39 countries suggest that COVID-19 perniolike lesions may persist as long as 150 days.⁵² In a time of many unknowns, these questions serve as a call to action for rigorous data collection, contribution to existing registries for dermatologic manifestations of COVID-19, and long-term follow-up of COVID-19 patients by the dermatology community. 

Pandemic Dermatology

The pandemic has posed unprecedented challenges for patient care. The use of hydroxychloroquine as a popular but unproven treatment for COVID-19, ⁵³ particularly early in the pandemic, has resulted in drug shortages for patients with lupus and other autoimmune skin diseases. Meanwhile, the need for patients with complex dermatologic conditions to receive systemic immunosuppression has had to be balanced against the associated risks during a global pandemic. To help dermatologists navigate this dilemma, various subspecialty groups have issued guidelines, including the COVID-19 Task Force of the Medical Dermatology Society and Society of Dermatology Hospitalists, which recommends a stepwise approach to shared decision-making with the goal of minimizing both the risk for disease flare and that of infection. The use of systemic steroids and rituximab, as well as the dose of immunosuppression—particularly broad-acting immunosuppression—should be limited where permitted. ⁵⁴

Rapid adoption of telemedicine and remote monitoring strategies has enabled dermatologists to provide safe and timely care when in-person visits have not been possible, including for patients with confirmed or suspected COVID-19, as well as for hospitalized patients. ^55-57 Use of telemedicine has facilitated preservation of personal protective equipment at a time when these important resources have been scarce. For patients with transportation or scheduling barriers, telemedicine has even expanded access to care. 

However, this strategy cannot completely replace comprehensive in-person evaluation. Variability in video and photographic quality limits evaluation, while in-person physical examination can reveal subtle morphologic clues necessary for diagnosis. ^{5 8} Additionally, unequal access to technology may disadvantage some patients. For dermatologists to provide optimal care and continue to contribute accurate and insightful observations into COVID-19, it is essential to be physically present in the clinic and in the hospital when necessary, caring for patients in need of dermatologic expertise. Creative management strategies developed during this time will benefit patients and expand the reach of the specialty . ^{5 8}

Final Thoughts

The COVID-19 pandemic has profoundly challenged the medical community and dermatology is no exception. By documenting and characterizing the diverse cutaneous manifestations of this novel disease, dermatologists have furthered understanding of its pathophysiology and management. By adapting quickly and developing creative ways to deliver care, dermatologists have found ways to contribute, both large and small. As we take stock at this juncture of the pandemic, it is clear there remains much to learn. We hope dermatologists will continue to take an active role in meeting the challenges of this time.

The virus that causes COVID-19—SARS-CoV-2—has infected more than 128 million individuals, resulting in more than 2.8 million deaths worldwide between December 2019 and April 2021. Disease mortality primarily is driven by hypoxemic respiratory failure and systemic hypercoagulability, resulting in multisystem organ failure.¹ With more than 17 million Americans infected, the virus is estimated to have impacted someone within the social circle of nearly every American.²

The COVID-19 pandemic has highlighted resource limitations, delayed elective and preventive care, and rapidly increased the adoption of telemedicine, presenting a host of new challenges to providers in every medical specialty, including dermatology. Although COVID-19 primarily is a respiratory disease, clinical manifestations have been observed in nearly every organ, including the skin. The cutaneous manifestations of COVID-19 provide insight into disease diagnosis, prognosis, and pathophysiology. In this article, we review the cutaneous manifestations of COVID-19 and explore the state of knowledge regarding their pathophysiology and clinical significance. Finally, we discuss the role of dermatology consultants in the care of patients with COVID-19, and the impact of the pandemic on the field of dermatology. 

Prevalence of Cutaneous Findings in COVID-19

Early reports characterizing the clinical presentation of patients hospitalized with COVID-19 suggested skin findings associated with the disease were rare. Cohort studies from Europe, China, and New York City in January through March 2020 reported a low prevalence or made no mention of rash.^3-7 However, reports from dermatologists in Italy that emerged in May 2020 indicated a substantially higher proportion of cutaneous disease: 18 of 88 (20.4%) hospitalized patients were found to have cutaneous involvement, primarily consisting of erythematous rash, along with some cases of urticarial and vesicular lesions.⁸ In October 2020, a retrospective cohort study from Spain examining 2761 patients presenting to the emergency department or admitted to the hospital for COVID-19 found that 58 (2.1%) patients had skin lesions attributed to COVID-19.⁹

The wide range in reported prevalence of skin lesions may be due to variable involvement of dermatologic specialists in patient care, particularly in China.¹⁰ Some variation also may be due to variability in the timing of clinical examination, as well as demographic and clinical differences in patient populations. Of note, a multisystem inflammatory disease seen in US children subsequent to infection with COVID-19 has been associated with rash in as many as 74% of cases.¹¹ Although COVID-19 disproportionately impacts people with skin of color, there are few reports of cutaneous manifestations in that population,¹² highlighting the challenges of the dermatologic examination in individuals with darker skin and suggesting the prevalence of dermatologic disease in COVID-19 may be greater than reported. 

Morphologic Patterns of Cutaneous Involvement in COVID-19

Researchers in Europe and the United States have attempted to classify the cutaneous manifestations of COVID-19. A registry established through the American Academy of Dermatology published a compilation of reports from 31 countries, totaling 716 patient profiles.¹³ A prospective Spanish study detailed the cutaneous involvement of 375 patients with suspected or confirmed COVID-19.¹⁴ Together, these efforts have revealed several distinct patterns of cutaneous involvement associated with COVID-19 (Table).^9,15-18 

Vesicular Rash
Vesicular rash associated with COVID-19 has been described in several studies and case series^8,13,14 and is considered, along with the pseudopernio (or pseudochilblains) morphology, to be one of the more disease-specific patterns in COVID-19.^14,18 Vesicular rash appears to comprise roughly one-tenth of all COVID-19–associated rashes.^13,14 It usually is described as pruritic, with 72% to 83% of patients reporting itch.^13,16 

Small monomorphic or polymorphic vesicles predominantly on the trunk and to a lesser extent the extremities and head have been described by multiple authors.^14,16 Vesicular rash is most common among middle-aged individuals, with studies reporting median and mean ages ranging from 40.5 to 55 years.^9,13,14,16

Vesicular rash develops concurrent with or after other presenting symptoms of COVID-19; in 2 studies, vesicular rash preceded development of other symptoms in only 15% and 5.6% of cases, respectively.^13,14 Prognostically, vesicular rash is associated with moderate disease severity.^14,16 It may persist for an average of 8 to 10 days.^14,16,18

Histopathologic examination reveals basal layer vacuolar degeneration, hyperchromatic keratinocytes, acantholysis, and dyskeratosis.^9,16,18 

Urticarial Rash
Urticarial lesions represent approximately 7% to 19% of reported COVID-19–associated rashes.^9,13,14 Urticarial rashes in patients testing positive for SARS-CoV-2 primarily occur on the trunk.¹⁴ The urticaria, which typically last about 1 week,¹⁴ are seen most frequently in middle-aged patients (mean/median age, 42–48 years)^13,14 and are associated with pruritus, which has been reported in 74% to 92% of patients.^13,14 Urticarial lesions typically do not precede other symptoms of COVID-19 and are nonspecific, making them less useful diagnostically.¹⁴

Urticaria appears to be associated with more severe COVID-19 illness in several studies, but this finding may be confounded by several factors, including older age, increased tobacco use, and polypharmacy. Of 104 patients with reported urticarial rash and suspected or confirmed COVID-19 across 3 studies, only 1 death was reported.^9,13,14 

The histopathologic appearance is that of typical hives, demonstrating a perivascular infiltrate of lymphocytes and eosinophils with edema of the upper dermis.^9,19

Morbilliform Eruption
Morbilliform eruption is a commonly reported morphology associated with COVID-19, accounting for 20% to 47% of rashes.^9,13,14 This categorization may have limited utility from a diagnostic and prognostic perspective, given that morbilliform eruptions are common, nonspecific, and heterogenous and can arise from many causes.^9,13,14 Onset of morbilliform eruption appears to coincide with¹⁴ or follow^13,20,21 the development of other COVID-19–related symptoms, with 5% of patients reporting morbilliform rash as the initial manifestation of infection.^13,14 Morbilliform eruptions have been observed to occur in patients with more severe disease.^9,13,14

Certain morphologic subtypes, such as erythema multiforme–like, erythema elevatum diutinum–like, or pseudovesicular, may be more specific to COVID-19 infection.¹⁴ A small case series highlighted 4 patients with erythema multiforme–like eruptions, 3 of whom also were found to have petechial enanthem occurring after COVID-19 diagnosis; however, the investigators were unable to exclude drug reaction as a potential cause of rash in these patients.²² Another case series of 21 patients with COVID-19 and skin rash described a (primarily) petechial enanthem on the palate in 6 (28.5%) patients.²³ It is unclear to what extent oral enanthem may be underrecognized given that some physicians may be disinclined to remove the masks of known COVID-19–positive patients to examine the oral cavity.

The histologic appearance of morbilliform rash seen in association with COVID-19 has been described as spongiotic with interface dermatitis with perivascular lymphocytic inflammation.^9,21

COVID Toes, Pseudochilblains Rash, Perniolike Rash, and Acral Erythema/Edema
Of all the rashes associated with COVID-19, COVID toes, or pseudochilblains rash, has perhaps attracted the most attention. The characteristic violaceous erythema on the fingers and/or toes may be itchy or painful, presenting similar to idiopathic cases of pernio (Figure 1).¹⁴ The entity has been controversial because of an absence of a clear correlation with a positive SARS-CoV-2 polymerase chain reaction test or antibodies to the virus in a subset of reported cases.^24,25 Onset of the rash late in the disease course, generally after symptom resolution in mild or asymptomatic cases, may explain the absence of viral DNA in the nasopharynx by the time of lesion appearance.^14,26 Seronegative patients may have cleared SARS-CoV-2 infection before humoral immunity could occur via a strong type 1 interferon response.²⁵

Across 3 studies, perniolike skin lesions constituted 18% to 29% of COVID-19–associated skin findings^9,13,14 and persisted for an average of 12 to 14 days.^13,14 Perniolike lesions portend a favorable outcome; patients with COVID toes rarely present with systemic symptoms or laboratory or imaging abnormalities⁹ and less commonly require hospitalization for severe illness. Perniolike lesions have been reported most frequently in younger patients, with a median or mean age of 32 to 35 years.^13,14

Histology demonstrates lichenoid dermatitis with perivascular and periadnexal lymphocytic infiltrates.⁹ Notably, one study observed interface dermatitis of the intraepidermal portion of the acrosyringium, a rare finding in chilblain lupus, in 83% of patients (N=40).²⁵ Direct immunofluorescence demonstrates a vasculopathic pattern, with some patients showing deposition of IgM or IgG, C3, and fibrinogen in dermal blood vessels. Vascular C9 deposits also have been demonstrated on immunohistochemistry.⁹ Biopsies of perniolike lesions in COVID-19 patients have demonstrated the presence of SARS-CoV-2 RNA,²⁷ have identified SARS-CoV-2 spike protein in endothelial cells on immunohistochemistry, and have visualized intracytoplasmic viral particles in vascular endothelium on electron microscopy.²⁸

Livedoid Rash/Retiform Purpura
Netlike purpuric or violaceous patches signifying vessel damage or occlusion have been seen in association with COVID-19, constituting approximately 6% of COVID-19–associated skin findings in 2 studies.^13,14 Livedoid rash (Figure 2) and retiform purpura (Figure 3) are associated with older age and occur primarily in severely ill patients, including those requiring intensive care. In a registry of 716 patients with COVID-19, 100% of patients with retiform purpura were hospitalized, and 82% had acute respiratory distress syndrome.¹³ In another study, 33% (7/21) of patients with livedoid and necrotic lesions required intensive care, and 10% (2/21) died.¹⁴

Multisystem Inflammatory Disease in Children

A hyperinflammatory syndrome similar to Kawasaki disease and toxic shock syndrome associated with mucocutaneous, cardiac, and gastrointestinal manifestations has been reported following COVID-19 infection.³¹ This syndrome, known as multisystem inflammatory syndrome in children (MIS-C), predominantly affects adolescents and children older than 5 years,¹¹ typically occurs 2 to 4 weeks after infection, and appears to be at least 100-times less common than COVID-19 infection among the same age group.³¹ Sixty percent³¹ to 74%¹¹ of affected patients have mucocutaneous involvement, with the most common clinical findings being conjunctival injection, palmoplantar erythema, lip hyperemia, periorbital erythema and edema, strawberry tongue, and malar erythema, respectively.³²

Because this condition appears to reflect an immune response to the virus, the majority of cases demonstrate negative SARS-CoV-2 polymerase chain reaction and positive antibody testing.³³ Although cutaneous findings are similar to those seen in Kawasaki disease, certain findings have been noted in MIS-C that are not typical of Kawasaki disease, including heliotrope rash–like periorbital edema and erythema as well as erythema infectiosum–like malar erythema and reticulated erythematous eruptions.³²

The course of MIS-C can be severe; in one case series of patients presenting with MIS-C, 80% (79/99) required intensive care unit admission, with 10% requiring mechanical ventilation and 2% of patients dying during admission.³¹ Cardiac dysfunction, coagulopathy, and gastrointestinal symptoms are common.^11,31 It has been postulated that a superantigenlike region of the SARS-CoV-2 spike protein, similar to that of staphylococcal enterotoxin B, may underlie MIS-C and account for its similarities to toxic shock syndrome.³⁴ Of note, a similar multisystem inflammatory syndrome associated with COVID-19 also has been described in adults, and it too may present with rash as a cardinal feature.³⁵

Pathophysiology of COVID-19: What the Skin May Reveal About the Disease

The diverse range of cutaneous manifestations in COVID-19 reflects a spectrum of host immunologicresponses to SARS-CoV-2 and may inform the pathophysiology of the disease as well as potential treatment modalities.

Host Response to SARS-CoV-2
The body’s response to viral infection is 2-pronged, involving activation of cellular antiviral defenses mediated by type I and III interferons, as well as recruitment of leukocytes, mobilized by cytokines and chemokines.^36,37 Infection with SARS-CoV-2 results in a unique inflammatory response characterized by suppression of interferons, juxtaposed with a rampant proinflammatory cytokine and chemokine response, reminiscent of a cytokine storm. Reflective of this imbalance, a study of 50 COVID-19 patients and 20 healthy controls found decreased natural killer cells and CD3⁺ T cells in COVID-19 patients, particularly severely or critically ill patients, with an increase in B cells and monocytes.³⁸ This distinctive immune imbalance positions SARS-CoV-2 to thrive in the absence of inhibitory interferon activity while submitting the host to the deleterious effects of a cytokine surge.³⁶

Type I Interferons
The perniolike lesions associated with mild COVID-19 disease¹⁴ may represent a robust immune response via effective stimulation of type I interferons (IFN-1). Similar perniolike lesions are observed in Aicardi-Goutières syndrome³⁷ and familial chilblain lupus, hereditary interferonopathies associated with mutations in the TREX1 (three prime repair exonuclease 1) gene and characterized by inappropriate upregulation of IFN-1,³⁹ resulting in chilblains. It has been suggested that perniolike lesions in COVID-19 result from IFN-1 activation—a robust effective immunologic response to the virus.^14,26,40

On the other end of the spectrum, patients with severe COVID-19 may have a blunted IFN-1 response and reduced IFN-1–stimulated gene expression.^36,38 Notably, low IFN-1 response preceded clinical deterioration and was associated with increased risk for evolution to critical illness.³⁸ Severe disease from COVID-19 also is more commonly observed in older patients and those with comorbidities,¹ both of which are known factors associated with depressed IFN-1 function.^38,41 Reflective of this disparate IFN-1 response, biopsies of COVID-19 perniosis have demonstrated striking expression of myxovirus resistance protein A (MXA), a marker for IFN-1 signaling in tissue, whereas its expression is absent in COVID-19 livedo/retiform purpura.²⁷

Familial chilblain lupus may be effectively treated by the Janus kinase inhibitor baricitinib,³⁹ which inhibits IFN-1 signaling. Baricitinib recently received emergency use authorization by the US Food and Drug Administration for treatment of severe COVID-19 pneumonia,^42,43 hinting to disordered IFN-1 signaling in the COVID-19 pathophysiology.

The impaired IFN-1 response in COVID-19 patients may be due to a unique characteristic of SARS-CoV-2: its ORF3b gene is a potent IFN-1 antagonist. In a series of experiments comparing SARS-CoV-2 to the related virus severe acute respiratory disease coronavirus (which was responsible for an epidemic in 2002), Konno et al⁴⁴ found that SARS-CoV-2 is more effectively able to downregulate host IFN-1, likely due to premature stop codons on ORF3b that produce a truncated version of the gene with amplified anti–IFN-1 activity.

 Cytokine Storm and Coagulation Cascade
This dulled interferon response is juxtaposed with a surge of inflammatory chemokines and cytokines, including IL-6, IL-8, IL-10, and tumor necrosis factor α, impairing innate immunity and leading to end-organ damage. This inflammatory response is associated with the influx of innate immune cells, specifically neutrophils and monocytes, which likely contribute to lung injury in COVID-19 acute respiratory distress syndrome.³⁸ It also is thought to lead to downstream activation of coagulation, with a high incidence of thrombotic events observed in patients with severe COVID-19.¹ In a retrospective study of 184 intensive care patients with COVID-19 receiving at least standard doses of thromboprophylaxis, venous thromboembolism occurred in 27% and arterial thrombotic events occurred in 3.7%.⁴⁵

Livedo racemosa and retiform purpura are cutaneous markers of hypercoagulability, which indicate an increased risk for systemic clotting in COVID-19. A positive feedback loop between the complement and coagulation cascades appears to be important.^{13,14,29,46-48} In addition, a few studies have reported antiphospholipid antibody positivity in hospitalized COVID-19 patients.^49,50

The high incidence of coagulopathy in severe COVID-19 has prompted many institutions to develop aggressive prophylactic anticoagulation protocols. Elevation of proinflammatory cytokines and observation of terminal complement activation in the skin and other organs has led to therapeutic trials of IL-6 inhibitors such as tocilizumab,⁵¹ complement inhibitors such as eculizumab, and Janus kinase inhibitors such as ruxolitinib and baricitinib.^42,48

COVID Long-Haulers
The long-term effects of immune dysregulation in COVID-19 patients remain to be seen. Viral triggering of autoimmune disease is a well-established phenomenon, seen in DRESS (drug reaction with eosinophilia and systemic symptoms) syndrome and other dermatologic diseases, raising the possibility that dermatologists will see a rising incidence of cutaneous autoimmune disease in the aftermath of the pandemic. Disordered interferon stimulation could lead to increased incidence of interferon-mediated disorders, such as sarcoidosis and other granulomatous diseases. Vasculitislike skin lesions could persist beyond the acute infectious period. Recent data from a registry of 990 COVID-19 cases from 39 countries suggest that COVID-19 perniolike lesions may persist as long as 150 days.⁵² In a time of many unknowns, these questions serve as a call to action for rigorous data collection, contribution to existing registries for dermatologic manifestations of COVID-19, and long-term follow-up of COVID-19 patients by the dermatology community. 

Pandemic Dermatology

The pandemic has posed unprecedented challenges for patient care. The use of hydroxychloroquine as a popular but unproven treatment for COVID-19, ⁵³ particularly early in the pandemic, has resulted in drug shortages for patients with lupus and other autoimmune skin diseases. Meanwhile, the need for patients with complex dermatologic conditions to receive systemic immunosuppression has had to be balanced against the associated risks during a global pandemic. To help dermatologists navigate this dilemma, various subspecialty groups have issued guidelines, including the COVID-19 Task Force of the Medical Dermatology Society and Society of Dermatology Hospitalists, which recommends a stepwise approach to shared decision-making with the goal of minimizing both the risk for disease flare and that of infection. The use of systemic steroids and rituximab, as well as the dose of immunosuppression—particularly broad-acting immunosuppression—should be limited where permitted. ⁵⁴

Rapid adoption of telemedicine and remote monitoring strategies has enabled dermatologists to provide safe and timely care when in-person visits have not been possible, including for patients with confirmed or suspected COVID-19, as well as for hospitalized patients. ^55-57 Use of telemedicine has facilitated preservation of personal protective equipment at a time when these important resources have been scarce. For patients with transportation or scheduling barriers, telemedicine has even expanded access to care. 

However, this strategy cannot completely replace comprehensive in-person evaluation. Variability in video and photographic quality limits evaluation, while in-person physical examination can reveal subtle morphologic clues necessary for diagnosis. ^{5 8} Additionally, unequal access to technology may disadvantage some patients. For dermatologists to provide optimal care and continue to contribute accurate and insightful observations into COVID-19, it is essential to be physically present in the clinic and in the hospital when necessary, caring for patients in need of dermatologic expertise. Creative management strategies developed during this time will benefit patients and expand the reach of the specialty . ^{5 8}

Final Thoughts

The COVID-19 pandemic has profoundly challenged the medical community and dermatology is no exception. By documenting and characterizing the diverse cutaneous manifestations of this novel disease, dermatologists have furthered understanding of its pathophysiology and management. By adapting quickly and developing creative ways to deliver care, dermatologists have found ways to contribute, both large and small. As we take stock at this juncture of the pandemic, it is clear there remains much to learn. We hope dermatologists will continue to take an active role in meeting the challenges of this time.

Itch is one of the most protean manifestations of skin disease and can take a substantial physical and emotional toll on patients. For physicians, it is a frequent—if often dreaded—patient concern with a rising incidence. Lack of specific itch therapies as well as associations with multiple dermatologic conditions, including xerosis, psoriasis, atopic dermatitis, cutaneous lymphoma, contact dermatitis, and internal malignancies, make management of these itchy patients challenging and deserving of our attention. Studies evaluating patients with chronic pruritus identified a considerable impact on health-related quality of life, including development of depression, inability to perform activities of daily living, and sleep difficulties. ¹

How to Classify Itching

Itch, or pruritus, originally was defined as an unpleasant sensation that provokes the desire to scratch,² but this definition likely limits our ability to assess itch. The urge to scratch the skin to relieve the itch is sometimes a reflex of the muscles triggered by the spinal cord that can be either conscious or unconscious. If 2 patients present with itch, does the patient with more excoriated skin experience more severe itch? Conversely, does the patient who scratches less have an equivalent decrease in itch severity? Although it is tempting to quantify itch through physical signs such as excoriations, it ultimately is a subjective symptom that is difficult to assess.

Pain is another complex subjective symptom but is one that has been better studied. A previous intensity theory postulated that itch is a form of pain: low-intensity noxious stimuli are perceived as itch, while high-intensity stimuli are perceived as pain. Over time, our understanding of itch evolved, and it became clear that a specific neuronal pathway for itch also exists.³ However, the pathophysiology of itch and pain remain intertwined. Scratching may elicit pain, providing a change in sensation that replaces the itch, whereas opioid analgesics suppress pain but may worsen the itch.

We are gaining a better understanding of the biology and classification of itch, which will hopefully enable the development of new measures to accurately assess itch. Four main categories of itch currently exist: neurogenic, psychogenic, neuropathic, and pruritoceptive.⁴ Patients may have one or multiple types of itch, which can be differentiated clinically and biochemically. Neurogenic (also known as systemic) itch is transmitted via the central nervous system with possible involvement of itch-specific neurons in the spinal cord and encompasses itch associated with pruritus from other organ systems. As the term implies, psychogenic itch is associated with psychiatric disorders. Neuropathic itch is generated from the inappropriate firing of peripheral or central sensory neurons in the absence of pruritogenic stimuli, which can be seen in notalgia paresthetica, brachioradial pruritus, and postherpetic neuralgia. Pruritoceptive itch most commonly is encountered in dermatology and is associated with skin inflammation or other dermatoses.⁴

How to Assess Itch Quantitatively

There currently are 2 major questions about quantitative assessments of itch. First, how do we measure itch in studies that are designed to relieve a different skin disease that is associated with itch? Most clinical trials investigating therapeutic options for atopic dermatitis and psoriasis now include itch assessment and improvement as a secondary outcome. Second, how do we measure itch in studies that are designed with relief of itch as the primary end point? Both of these scenarios require a fundamental set of decisions. Itch clearly is a subjective experience, but it also is one that can be local, regional, generalized, or transitory. Just as with pain, an individual can be distracted from their itch to some extent and consequently experience it more acutely when there are fewer stimuli in their environment. Classically, patients will report that itching is worse at night, preventing them from sleeping. Sleep disruption previously has been demonstrated.⁵ Of course, the environment also can exacerbate itch, as dry air and in some cases humidity can flare the sensation.

Fundamentally, therefore, the questions that are asked to assess itch are incredibly relevant, and there is a matrix of possible avenues of inquiry. Should you measure the peak itch in one area or the peak itch overall? Is the duration, the frequency, or the persistence of the itching most relevant? What is the correct time frame in which to do an assessment: the last 24 hours, the last 48 hours, or the last week? Because these parameters have been so challenging, most investigators have used a visual analog scale, similar to what is used to assess pain, at a 24-hour interval to decrease recall bias. The most commonly employed tool is the itch numeric rating scale (NRS), which asks patients to rate their symptoms on a scale of 0 (no itch) to 10 (worst imaginable itch). Although the psychometric properties of the itch NRS have been validated, debate still exists as to whether the itch NRS is best administered at a specific time of day or if it should be updated to evaluate peak pruritus scores explicitly. Regardless, implementing these scales often is time consuming and burdensome in the clinical trial setting, as participants are asked to complete daily diaries at the same time each day using either paper forms or electronic tablets.

Once scores are collected, we then need to quantitate a meaningful difference in itch. For pain, there has been some acceptance of a 30% difference, or a 2-point reduction, as being clinically meaningful; however, there was substantial debate at the time of the approval of ixekizumab as to whether that was a similarly appropriate threshold for itch. Using data from ixekizumab phase 2 and phase 3 trials, a 4-point reduction in itch NRS was found to be optimal for evaluating clinically significant changes in moderate to severe psoriasis.⁶ A more recent study of the validity of the itch NRS in prurigo nodularis suggested a 1-point change was correlated with minimal clinical improvement.⁷ Thus, the interesting question of how assessment of itch varies across clinical trials and disease states needs to be raised. Psoriasis classically has been thought of as not particularly itchy, and atopic dermatitis and prurigo nodularis have been regarded as extraordinarily itchy, yet one study comparing baseline itch scores in psoriasis and atopic dermatitis suggested that the experience actually is somewhat similar.⁸

Final Thoughts

The subjective nature of itch makes NRSs our best option at this time, but the best disease severity assessment tools are objective, sensitive, and generalizable. Unfortunately, we do not have such tools available to us yet, but technology—smart devices to monitor nocturnal scratching and machine learning algorithms that use electromagnetic impact to capture motion associated with itching and scratching⁹—may offer new objective measures for itch that can be used to further validate the current itch NRS. Even if these technology-based approaches become the standard of measurement, they will certainly help us understand what we are measuring. And even better, the focus on how to develop meaningful end points around the improvement of itch will likely lead us to measure it more and drive the development of therapeutics that address the effect and consequences of this pernicious problem.

Itch is one of the most protean manifestations of skin disease and can take a substantial physical and emotional toll on patients. For physicians, it is a frequent—if often dreaded—patient concern with a rising incidence. Lack of specific itch therapies as well as associations with multiple dermatologic conditions, including xerosis, psoriasis, atopic dermatitis, cutaneous lymphoma, contact dermatitis, and internal malignancies, make management of these itchy patients challenging and deserving of our attention. Studies evaluating patients with chronic pruritus identified a considerable impact on health-related quality of life, including development of depression, inability to perform activities of daily living, and sleep difficulties. ¹

How to Classify Itching

Itch, or pruritus, originally was defined as an unpleasant sensation that provokes the desire to scratch,² but this definition likely limits our ability to assess itch. The urge to scratch the skin to relieve the itch is sometimes a reflex of the muscles triggered by the spinal cord that can be either conscious or unconscious. If 2 patients present with itch, does the patient with more excoriated skin experience more severe itch? Conversely, does the patient who scratches less have an equivalent decrease in itch severity? Although it is tempting to quantify itch through physical signs such as excoriations, it ultimately is a subjective symptom that is difficult to assess.

Pain is another complex subjective symptom but is one that has been better studied. A previous intensity theory postulated that itch is a form of pain: low-intensity noxious stimuli are perceived as itch, while high-intensity stimuli are perceived as pain. Over time, our understanding of itch evolved, and it became clear that a specific neuronal pathway for itch also exists.³ However, the pathophysiology of itch and pain remain intertwined. Scratching may elicit pain, providing a change in sensation that replaces the itch, whereas opioid analgesics suppress pain but may worsen the itch.

We are gaining a better understanding of the biology and classification of itch, which will hopefully enable the development of new measures to accurately assess itch. Four main categories of itch currently exist: neurogenic, psychogenic, neuropathic, and pruritoceptive.⁴ Patients may have one or multiple types of itch, which can be differentiated clinically and biochemically. Neurogenic (also known as systemic) itch is transmitted via the central nervous system with possible involvement of itch-specific neurons in the spinal cord and encompasses itch associated with pruritus from other organ systems. As the term implies, psychogenic itch is associated with psychiatric disorders. Neuropathic itch is generated from the inappropriate firing of peripheral or central sensory neurons in the absence of pruritogenic stimuli, which can be seen in notalgia paresthetica, brachioradial pruritus, and postherpetic neuralgia. Pruritoceptive itch most commonly is encountered in dermatology and is associated with skin inflammation or other dermatoses.⁴

How to Assess Itch Quantitatively

There currently are 2 major questions about quantitative assessments of itch. First, how do we measure itch in studies that are designed to relieve a different skin disease that is associated with itch? Most clinical trials investigating therapeutic options for atopic dermatitis and psoriasis now include itch assessment and improvement as a secondary outcome. Second, how do we measure itch in studies that are designed with relief of itch as the primary end point? Both of these scenarios require a fundamental set of decisions. Itch clearly is a subjective experience, but it also is one that can be local, regional, generalized, or transitory. Just as with pain, an individual can be distracted from their itch to some extent and consequently experience it more acutely when there are fewer stimuli in their environment. Classically, patients will report that itching is worse at night, preventing them from sleeping. Sleep disruption previously has been demonstrated.⁵ Of course, the environment also can exacerbate itch, as dry air and in some cases humidity can flare the sensation.

Fundamentally, therefore, the questions that are asked to assess itch are incredibly relevant, and there is a matrix of possible avenues of inquiry. Should you measure the peak itch in one area or the peak itch overall? Is the duration, the frequency, or the persistence of the itching most relevant? What is the correct time frame in which to do an assessment: the last 24 hours, the last 48 hours, or the last week? Because these parameters have been so challenging, most investigators have used a visual analog scale, similar to what is used to assess pain, at a 24-hour interval to decrease recall bias. The most commonly employed tool is the itch numeric rating scale (NRS), which asks patients to rate their symptoms on a scale of 0 (no itch) to 10 (worst imaginable itch). Although the psychometric properties of the itch NRS have been validated, debate still exists as to whether the itch NRS is best administered at a specific time of day or if it should be updated to evaluate peak pruritus scores explicitly. Regardless, implementing these scales often is time consuming and burdensome in the clinical trial setting, as participants are asked to complete daily diaries at the same time each day using either paper forms or electronic tablets.

Once scores are collected, we then need to quantitate a meaningful difference in itch. For pain, there has been some acceptance of a 30% difference, or a 2-point reduction, as being clinically meaningful; however, there was substantial debate at the time of the approval of ixekizumab as to whether that was a similarly appropriate threshold for itch. Using data from ixekizumab phase 2 and phase 3 trials, a 4-point reduction in itch NRS was found to be optimal for evaluating clinically significant changes in moderate to severe psoriasis.⁶ A more recent study of the validity of the itch NRS in prurigo nodularis suggested a 1-point change was correlated with minimal clinical improvement.⁷ Thus, the interesting question of how assessment of itch varies across clinical trials and disease states needs to be raised. Psoriasis classically has been thought of as not particularly itchy, and atopic dermatitis and prurigo nodularis have been regarded as extraordinarily itchy, yet one study comparing baseline itch scores in psoriasis and atopic dermatitis suggested that the experience actually is somewhat similar.⁸

Final Thoughts

The subjective nature of itch makes NRSs our best option at this time, but the best disease severity assessment tools are objective, sensitive, and generalizable. Unfortunately, we do not have such tools available to us yet, but technology—smart devices to monitor nocturnal scratching and machine learning algorithms that use electromagnetic impact to capture motion associated with itching and scratching⁹—may offer new objective measures for itch that can be used to further validate the current itch NRS. Even if these technology-based approaches become the standard of measurement, they will certainly help us understand what we are measuring. And even better, the focus on how to develop meaningful end points around the improvement of itch will likely lead us to measure it more and drive the development of therapeutics that address the effect and consequences of this pernicious problem.

Itch is one of the most protean manifestations of skin disease and can take a substantial physical and emotional toll on patients. For physicians, it is a frequent—if often dreaded—patient concern with a rising incidence. Lack of specific itch therapies as well as associations with multiple dermatologic conditions, including xerosis, psoriasis, atopic dermatitis, cutaneous lymphoma, contact dermatitis, and internal malignancies, make management of these itchy patients challenging and deserving of our attention. Studies evaluating patients with chronic pruritus identified a considerable impact on health-related quality of life, including development of depression, inability to perform activities of daily living, and sleep difficulties. ¹

How to Classify Itching

Itch, or pruritus, originally was defined as an unpleasant sensation that provokes the desire to scratch,² but this definition likely limits our ability to assess itch. The urge to scratch the skin to relieve the itch is sometimes a reflex of the muscles triggered by the spinal cord that can be either conscious or unconscious. If 2 patients present with itch, does the patient with more excoriated skin experience more severe itch? Conversely, does the patient who scratches less have an equivalent decrease in itch severity? Although it is tempting to quantify itch through physical signs such as excoriations, it ultimately is a subjective symptom that is difficult to assess.

Pain is another complex subjective symptom but is one that has been better studied. A previous intensity theory postulated that itch is a form of pain: low-intensity noxious stimuli are perceived as itch, while high-intensity stimuli are perceived as pain. Over time, our understanding of itch evolved, and it became clear that a specific neuronal pathway for itch also exists.³ However, the pathophysiology of itch and pain remain intertwined. Scratching may elicit pain, providing a change in sensation that replaces the itch, whereas opioid analgesics suppress pain but may worsen the itch.

We are gaining a better understanding of the biology and classification of itch, which will hopefully enable the development of new measures to accurately assess itch. Four main categories of itch currently exist: neurogenic, psychogenic, neuropathic, and pruritoceptive.⁴ Patients may have one or multiple types of itch, which can be differentiated clinically and biochemically. Neurogenic (also known as systemic) itch is transmitted via the central nervous system with possible involvement of itch-specific neurons in the spinal cord and encompasses itch associated with pruritus from other organ systems. As the term implies, psychogenic itch is associated with psychiatric disorders. Neuropathic itch is generated from the inappropriate firing of peripheral or central sensory neurons in the absence of pruritogenic stimuli, which can be seen in notalgia paresthetica, brachioradial pruritus, and postherpetic neuralgia. Pruritoceptive itch most commonly is encountered in dermatology and is associated with skin inflammation or other dermatoses.⁴

How to Assess Itch Quantitatively

There currently are 2 major questions about quantitative assessments of itch. First, how do we measure itch in studies that are designed to relieve a different skin disease that is associated with itch? Most clinical trials investigating therapeutic options for atopic dermatitis and psoriasis now include itch assessment and improvement as a secondary outcome. Second, how do we measure itch in studies that are designed with relief of itch as the primary end point? Both of these scenarios require a fundamental set of decisions. Itch clearly is a subjective experience, but it also is one that can be local, regional, generalized, or transitory. Just as with pain, an individual can be distracted from their itch to some extent and consequently experience it more acutely when there are fewer stimuli in their environment. Classically, patients will report that itching is worse at night, preventing them from sleeping. Sleep disruption previously has been demonstrated.⁵ Of course, the environment also can exacerbate itch, as dry air and in some cases humidity can flare the sensation.

Fundamentally, therefore, the questions that are asked to assess itch are incredibly relevant, and there is a matrix of possible avenues of inquiry. Should you measure the peak itch in one area or the peak itch overall? Is the duration, the frequency, or the persistence of the itching most relevant? What is the correct time frame in which to do an assessment: the last 24 hours, the last 48 hours, or the last week? Because these parameters have been so challenging, most investigators have used a visual analog scale, similar to what is used to assess pain, at a 24-hour interval to decrease recall bias. The most commonly employed tool is the itch numeric rating scale (NRS), which asks patients to rate their symptoms on a scale of 0 (no itch) to 10 (worst imaginable itch). Although the psychometric properties of the itch NRS have been validated, debate still exists as to whether the itch NRS is best administered at a specific time of day or if it should be updated to evaluate peak pruritus scores explicitly. Regardless, implementing these scales often is time consuming and burdensome in the clinical trial setting, as participants are asked to complete daily diaries at the same time each day using either paper forms or electronic tablets.

Once scores are collected, we then need to quantitate a meaningful difference in itch. For pain, there has been some acceptance of a 30% difference, or a 2-point reduction, as being clinically meaningful; however, there was substantial debate at the time of the approval of ixekizumab as to whether that was a similarly appropriate threshold for itch. Using data from ixekizumab phase 2 and phase 3 trials, a 4-point reduction in itch NRS was found to be optimal for evaluating clinically significant changes in moderate to severe psoriasis.⁶ A more recent study of the validity of the itch NRS in prurigo nodularis suggested a 1-point change was correlated with minimal clinical improvement.⁷ Thus, the interesting question of how assessment of itch varies across clinical trials and disease states needs to be raised. Psoriasis classically has been thought of as not particularly itchy, and atopic dermatitis and prurigo nodularis have been regarded as extraordinarily itchy, yet one study comparing baseline itch scores in psoriasis and atopic dermatitis suggested that the experience actually is somewhat similar.⁸

Final Thoughts

The subjective nature of itch makes NRSs our best option at this time, but the best disease severity assessment tools are objective, sensitive, and generalizable. Unfortunately, we do not have such tools available to us yet, but technology—smart devices to monitor nocturnal scratching and machine learning algorithms that use electromagnetic impact to capture motion associated with itching and scratching⁹—may offer new objective measures for itch that can be used to further validate the current itch NRS. Even if these technology-based approaches become the standard of measurement, they will certainly help us understand what we are measuring. And even better, the focus on how to develop meaningful end points around the improvement of itch will likely lead us to measure it more and drive the development of therapeutics that address the effect and consequences of this pernicious problem.

To the Editor:

Erosive lichen planus (LP) often is painful, debilitating, and resistant to topical therapy making it both a diagnostic and therapeutic challenge. We report the case of an elderly woman with isolated perianal erosive LP, a rare clinical manifestation. We also review cases of erosive perianal LP reported in the literature.

A 72-year-old woman was referred to our dermatology clinic for evaluation of multiple pruritic and painful perianal lesions of 1 year’s duration. The lesions had remained stable since onset, with no other reported lesions elsewhere on body, including the mucosae. Her medical history was notable for rheumatoid arthritis, osteoporosis, hypercholesterolemia, and hypertension. She was taking methotrexate, folic acid, abatacept, alendronate, atorvastatin, and lisinopril. The patient reported she had been using abatacept for 3 years and lisinopril for 2 years. Her primary care physician initially treated the lesions as hemorrhoids but referred her to a gastroenterologist when they failed to improve. Gastroenterology evaluated the patient, and a colonoscopy was performed with unremarkable results. Thus, she was referred to dermatology for further evaluation.

Physical examination revealed 2 tender, sharply defined, angulated erosions with irregular violaceous borders involving the perianal skin (Figure 1). A biopsy of one of the lesions was taken. Histopathologic examination revealed acanthosis of the epidermis with slight compact hyperkeratosis, scattered dyskeratotic keratinocytes, and a dense bandlike lymphohistiocytic infiltrate that obliterated the dermoepidermal junction (Figure 2). A diagnosis of perianal erosive LP was made. The patient was prescribed mometasone ointment 0.1% daily with notable improvement after 2 months.

Treatment of LP varies depending on the location and subtype of the lesions and is primarily aimed at improving symptoms. Topical corticosteroids are the standard treatment of LP; however, there is limited evidence regarding their efficacy for mucosal LP. Although randomized controlled trials assessing the efficacy of different interventions on oral erosive LP are available in the literature,¹⁵ there is a paucity of studies addressing this topic for genital or perianal LP. A review of the literature regarding perianal erosive LP suggests good response to high-potency topical steroids and calcineurin inhibitors with resolution of lesions within 3 to 4 weeks.^11,15-18

Erosive LP is a painful variant that can cause erosions, ulcerations, and scarring. It rarely is seen in the perianal region alone and presents a diagnostic challenge. Treatment with high-potency topical steroid therapy seems to be effective in the few cases that have been reported as well as in our case. More comprehensive data from randomized controlled trials would be needed to evaluate their efficacy compared to other therapies.

To the Editor:

Erosive lichen planus (LP) often is painful, debilitating, and resistant to topical therapy making it both a diagnostic and therapeutic challenge. We report the case of an elderly woman with isolated perianal erosive LP, a rare clinical manifestation. We also review cases of erosive perianal LP reported in the literature.

A 72-year-old woman was referred to our dermatology clinic for evaluation of multiple pruritic and painful perianal lesions of 1 year’s duration. The lesions had remained stable since onset, with no other reported lesions elsewhere on body, including the mucosae. Her medical history was notable for rheumatoid arthritis, osteoporosis, hypercholesterolemia, and hypertension. She was taking methotrexate, folic acid, abatacept, alendronate, atorvastatin, and lisinopril. The patient reported she had been using abatacept for 3 years and lisinopril for 2 years. Her primary care physician initially treated the lesions as hemorrhoids but referred her to a gastroenterologist when they failed to improve. Gastroenterology evaluated the patient, and a colonoscopy was performed with unremarkable results. Thus, she was referred to dermatology for further evaluation.

Physical examination revealed 2 tender, sharply defined, angulated erosions with irregular violaceous borders involving the perianal skin (Figure 1). A biopsy of one of the lesions was taken. Histopathologic examination revealed acanthosis of the epidermis with slight compact hyperkeratosis, scattered dyskeratotic keratinocytes, and a dense bandlike lymphohistiocytic infiltrate that obliterated the dermoepidermal junction (Figure 2). A diagnosis of perianal erosive LP was made. The patient was prescribed mometasone ointment 0.1% daily with notable improvement after 2 months.

Treatment of LP varies depending on the location and subtype of the lesions and is primarily aimed at improving symptoms. Topical corticosteroids are the standard treatment of LP; however, there is limited evidence regarding their efficacy for mucosal LP. Although randomized controlled trials assessing the efficacy of different interventions on oral erosive LP are available in the literature,¹⁵ there is a paucity of studies addressing this topic for genital or perianal LP. A review of the literature regarding perianal erosive LP suggests good response to high-potency topical steroids and calcineurin inhibitors with resolution of lesions within 3 to 4 weeks.^11,15-18

Erosive LP is a painful variant that can cause erosions, ulcerations, and scarring. It rarely is seen in the perianal region alone and presents a diagnostic challenge. Treatment with high-potency topical steroid therapy seems to be effective in the few cases that have been reported as well as in our case. More comprehensive data from randomized controlled trials would be needed to evaluate their efficacy compared to other therapies.

To the Editor:

Erosive lichen planus (LP) often is painful, debilitating, and resistant to topical therapy making it both a diagnostic and therapeutic challenge. We report the case of an elderly woman with isolated perianal erosive LP, a rare clinical manifestation. We also review cases of erosive perianal LP reported in the literature.

A 72-year-old woman was referred to our dermatology clinic for evaluation of multiple pruritic and painful perianal lesions of 1 year’s duration. The lesions had remained stable since onset, with no other reported lesions elsewhere on body, including the mucosae. Her medical history was notable for rheumatoid arthritis, osteoporosis, hypercholesterolemia, and hypertension. She was taking methotrexate, folic acid, abatacept, alendronate, atorvastatin, and lisinopril. The patient reported she had been using abatacept for 3 years and lisinopril for 2 years. Her primary care physician initially treated the lesions as hemorrhoids but referred her to a gastroenterologist when they failed to improve. Gastroenterology evaluated the patient, and a colonoscopy was performed with unremarkable results. Thus, she was referred to dermatology for further evaluation.

Physical examination revealed 2 tender, sharply defined, angulated erosions with irregular violaceous borders involving the perianal skin (Figure 1). A biopsy of one of the lesions was taken. Histopathologic examination revealed acanthosis of the epidermis with slight compact hyperkeratosis, scattered dyskeratotic keratinocytes, and a dense bandlike lymphohistiocytic infiltrate that obliterated the dermoepidermal junction (Figure 2). A diagnosis of perianal erosive LP was made. The patient was prescribed mometasone ointment 0.1% daily with notable improvement after 2 months.

Treatment of LP varies depending on the location and subtype of the lesions and is primarily aimed at improving symptoms. Topical corticosteroids are the standard treatment of LP; however, there is limited evidence regarding their efficacy for mucosal LP. Although randomized controlled trials assessing the efficacy of different interventions on oral erosive LP are available in the literature,¹⁵ there is a paucity of studies addressing this topic for genital or perianal LP. A review of the literature regarding perianal erosive LP suggests good response to high-potency topical steroids and calcineurin inhibitors with resolution of lesions within 3 to 4 weeks.^11,15-18

Erosive LP is a painful variant that can cause erosions, ulcerations, and scarring. It rarely is seen in the perianal region alone and presents a diagnostic challenge. Treatment with high-potency topical steroid therapy seems to be effective in the few cases that have been reported as well as in our case. More comprehensive data from randomized controlled trials would be needed to evaluate their efficacy compared to other therapies.

The Diagnosis: Cutaneous B-cell Lymphoma 

Histopathology revealed a dense and diffuse lymphocytic infiltrate throughout the dermis with occasional individual cell necrosis. On closer inspection, the infiltrate consisted of intermediate-sized lymphocytes, some with a vesiculated nucleus and ample amount of cytoplasm, while others contained hyperchromatic nuclei (Figure 1). These cells stained strongly positive for B-cell marker (CD20), while only a few mature lymphocytes demonstrated T-cell phenotype (CD3)(Figure 2).  

Although the patient recounted a 3-month history of lower leg edema, he also reported that the rash began a few weeks after his diagnosis of systemic B-cell follicular lymphoma. Throughout this time, he was seen by various physicians who attributed the edema and skin changes to chronic stasis, peripheral venous insufficiency, and diabetic peripheral neuropathy. His primary care physician prescribed an antifungal lotion, which he discontinued on his own due to lack of improvement. Upon arrival to the emergency department, he was started on intravenous cefazolin and subcutaneous heparin. Doppler ultrasonography of the legs was ordered to rule out a deep venous thrombosis. Dermatology was consulted and proceeded with a punch biopsy to investigate for cutaneous B-cell lymphoma (BCL) with a plan to follow up as an outpatient for results upon discharge. He also was prescribed triamcinolone ointment 0.1% twice daily for symptomatic relief. 

The patient's left axillary lymph node was biopsied for pathologic evaluation. Immunohistochemical staining revealed expression of B-cell markers CD20, CD79a, and PAX5, along with the antiapoptotic markers BCL-2 and BCL-6. Fluorescence in situ hybridization displayed gene rearrangements of BCL-2, BCL-6, and t(14;18)/IgH-BCL2 in the majority of cells. CD3 and CD5 immunostains were negative, indicating that T cells were not involved in this process. Flow cytometry identified a monoclonal κ B-cell population in 40% to 50% of the total cells, which co-expressed CD10, CD19, CD22, and CD38; the cells were negative for CD5, CD20, and CD23. Cell size was variably enlarged and CD71 positive, otherwise known as transferrin receptor 1, indicating the mediation of iron transport into cells of erythroid lineage that is necessary for proliferation.¹ Bone marrow core biopsy did not identify features of bone marrow involvement by the lymphoma. Based on these results, the patient was diagnosed with systemic B-cell follicular lymphoma grade 3b stage IIIA. Oncology initiated a systemic chemotherapy regimen with obinutuzumab, cyclophosphamide, doxorubicin hydrochloride (hydroxydaunorubicin), vincristine sulfate, and prednisone. 

Skin involvement in B-cell follicular lymphoma can be primary or secondary. Although all subtypes of BCL can have secondary cutaneous involvement, it is most common in advanced-stage disease (stages III or IV).² Cutaneous manifestations of primary cutaneous follicle-center lymphoma (PCFCL) and systemic/nodal follicular lymphoma secondarily involving the skin can be difficult to distinguish clinically and histopathologically; both appear as solitary or grouped plaques and nodules most commonly on the head, neck, or trunk, and rarely on the legs.³ Although the pathologic features of these two diagnoses can seem almost identical, it is important to differentiate them due to their differing prognosis and management. Patients with follicular lymphoma involving the skin are more likely than those with PCFCL to develop lymphadenopathy and B symptoms.³ Primary cutaneous follicle-center lymphoma also generally runs an indolent course and requires local therapy, while secondary involvement of the skin due to systemic/nodal follicular lymphoma has a worse prognosis and requires systemic chemotherapy treatment.⁴ 

Immunohistochemical markers are the most helpful tool used to distinguish PCFCL from systemic/nodal follicular lymphoma involving the skin. Tumors of B-cell origin are expected to express associated B-cell markers such as CD20, CD79a, and PAX5²; BCL-6, a marker of germinal center cells, also is expected to stain positive.² CD10 is positive in a majority of cases with a follicular growth pattern, while those with a diffuse pattern of growth may have a negative stain.² The most valuable histopathologic indicator differentiating primary and secondary skin involvement is the intensity of BCL-2 expression.⁵ The prognostic significance of the t(14;18)/IgH-BCL2 rearrangement is controversial, with rearrangement identified in more than 75% of systemic/nodal follicular lymphoma cases and less commonly found in PCFCL, with one report arguing an incidence ranging from 1% to 40%.⁵ 

A comprehensive history and physical examination are necessary to develop a differential diagnosis. Our patient's lower leg edema and extensive medical history made the diagnosis more complicated. Pitting edema was present on physical examination, making elephantiasis nostras verrucosa less likely, as it would instead present with nonpitting edema and a woody feel.⁶ Our patient did not have epidemiologic exposure to filariasis through foreign travel and did not present with any classic signs or symptoms of lymphatic filariasis, such as fever, eosinophilia, chyluria, or hydrocele.⁷ Although a negative history of HIV makes Kaposi sarcoma and bacillary angiomatosis less likely diagnoses, a biopsy would be useful to rule out these conditions. Positive inguinal lymphadenopathy present on physical examination may have contributed to lymphatic flow obstruction leading to the leg lymphedema in our patient. 

The Diagnosis: Cutaneous B-cell Lymphoma 

Histopathology revealed a dense and diffuse lymphocytic infiltrate throughout the dermis with occasional individual cell necrosis. On closer inspection, the infiltrate consisted of intermediate-sized lymphocytes, some with a vesiculated nucleus and ample amount of cytoplasm, while others contained hyperchromatic nuclei (Figure 1). These cells stained strongly positive for B-cell marker (CD20), while only a few mature lymphocytes demonstrated T-cell phenotype (CD3)(Figure 2).  

Although the patient recounted a 3-month history of lower leg edema, he also reported that the rash began a few weeks after his diagnosis of systemic B-cell follicular lymphoma. Throughout this time, he was seen by various physicians who attributed the edema and skin changes to chronic stasis, peripheral venous insufficiency, and diabetic peripheral neuropathy. His primary care physician prescribed an antifungal lotion, which he discontinued on his own due to lack of improvement. Upon arrival to the emergency department, he was started on intravenous cefazolin and subcutaneous heparin. Doppler ultrasonography of the legs was ordered to rule out a deep venous thrombosis. Dermatology was consulted and proceeded with a punch biopsy to investigate for cutaneous B-cell lymphoma (BCL) with a plan to follow up as an outpatient for results upon discharge. He also was prescribed triamcinolone ointment 0.1% twice daily for symptomatic relief. 

The patient's left axillary lymph node was biopsied for pathologic evaluation. Immunohistochemical staining revealed expression of B-cell markers CD20, CD79a, and PAX5, along with the antiapoptotic markers BCL-2 and BCL-6. Fluorescence in situ hybridization displayed gene rearrangements of BCL-2, BCL-6, and t(14;18)/IgH-BCL2 in the majority of cells. CD3 and CD5 immunostains were negative, indicating that T cells were not involved in this process. Flow cytometry identified a monoclonal κ B-cell population in 40% to 50% of the total cells, which co-expressed CD10, CD19, CD22, and CD38; the cells were negative for CD5, CD20, and CD23. Cell size was variably enlarged and CD71 positive, otherwise known as transferrin receptor 1, indicating the mediation of iron transport into cells of erythroid lineage that is necessary for proliferation.¹ Bone marrow core biopsy did not identify features of bone marrow involvement by the lymphoma. Based on these results, the patient was diagnosed with systemic B-cell follicular lymphoma grade 3b stage IIIA. Oncology initiated a systemic chemotherapy regimen with obinutuzumab, cyclophosphamide, doxorubicin hydrochloride (hydroxydaunorubicin), vincristine sulfate, and prednisone. 

Skin involvement in B-cell follicular lymphoma can be primary or secondary. Although all subtypes of BCL can have secondary cutaneous involvement, it is most common in advanced-stage disease (stages III or IV).² Cutaneous manifestations of primary cutaneous follicle-center lymphoma (PCFCL) and systemic/nodal follicular lymphoma secondarily involving the skin can be difficult to distinguish clinically and histopathologically; both appear as solitary or grouped plaques and nodules most commonly on the head, neck, or trunk, and rarely on the legs.³ Although the pathologic features of these two diagnoses can seem almost identical, it is important to differentiate them due to their differing prognosis and management. Patients with follicular lymphoma involving the skin are more likely than those with PCFCL to develop lymphadenopathy and B symptoms.³ Primary cutaneous follicle-center lymphoma also generally runs an indolent course and requires local therapy, while secondary involvement of the skin due to systemic/nodal follicular lymphoma has a worse prognosis and requires systemic chemotherapy treatment.⁴ 

Immunohistochemical markers are the most helpful tool used to distinguish PCFCL from systemic/nodal follicular lymphoma involving the skin. Tumors of B-cell origin are expected to express associated B-cell markers such as CD20, CD79a, and PAX5²; BCL-6, a marker of germinal center cells, also is expected to stain positive.² CD10 is positive in a majority of cases with a follicular growth pattern, while those with a diffuse pattern of growth may have a negative stain.² The most valuable histopathologic indicator differentiating primary and secondary skin involvement is the intensity of BCL-2 expression.⁵ The prognostic significance of the t(14;18)/IgH-BCL2 rearrangement is controversial, with rearrangement identified in more than 75% of systemic/nodal follicular lymphoma cases and less commonly found in PCFCL, with one report arguing an incidence ranging from 1% to 40%.⁵ 

A comprehensive history and physical examination are necessary to develop a differential diagnosis. Our patient's lower leg edema and extensive medical history made the diagnosis more complicated. Pitting edema was present on physical examination, making elephantiasis nostras verrucosa less likely, as it would instead present with nonpitting edema and a woody feel.⁶ Our patient did not have epidemiologic exposure to filariasis through foreign travel and did not present with any classic signs or symptoms of lymphatic filariasis, such as fever, eosinophilia, chyluria, or hydrocele.⁷ Although a negative history of HIV makes Kaposi sarcoma and bacillary angiomatosis less likely diagnoses, a biopsy would be useful to rule out these conditions. Positive inguinal lymphadenopathy present on physical examination may have contributed to lymphatic flow obstruction leading to the leg lymphedema in our patient. 

The Diagnosis: Cutaneous B-cell Lymphoma 

Histopathology revealed a dense and diffuse lymphocytic infiltrate throughout the dermis with occasional individual cell necrosis. On closer inspection, the infiltrate consisted of intermediate-sized lymphocytes, some with a vesiculated nucleus and ample amount of cytoplasm, while others contained hyperchromatic nuclei (Figure 1). These cells stained strongly positive for B-cell marker (CD20), while only a few mature lymphocytes demonstrated T-cell phenotype (CD3)(Figure 2).  

Although the patient recounted a 3-month history of lower leg edema, he also reported that the rash began a few weeks after his diagnosis of systemic B-cell follicular lymphoma. Throughout this time, he was seen by various physicians who attributed the edema and skin changes to chronic stasis, peripheral venous insufficiency, and diabetic peripheral neuropathy. His primary care physician prescribed an antifungal lotion, which he discontinued on his own due to lack of improvement. Upon arrival to the emergency department, he was started on intravenous cefazolin and subcutaneous heparin. Doppler ultrasonography of the legs was ordered to rule out a deep venous thrombosis. Dermatology was consulted and proceeded with a punch biopsy to investigate for cutaneous B-cell lymphoma (BCL) with a plan to follow up as an outpatient for results upon discharge. He also was prescribed triamcinolone ointment 0.1% twice daily for symptomatic relief. 

The patient's left axillary lymph node was biopsied for pathologic evaluation. Immunohistochemical staining revealed expression of B-cell markers CD20, CD79a, and PAX5, along with the antiapoptotic markers BCL-2 and BCL-6. Fluorescence in situ hybridization displayed gene rearrangements of BCL-2, BCL-6, and t(14;18)/IgH-BCL2 in the majority of cells. CD3 and CD5 immunostains were negative, indicating that T cells were not involved in this process. Flow cytometry identified a monoclonal κ B-cell population in 40% to 50% of the total cells, which co-expressed CD10, CD19, CD22, and CD38; the cells were negative for CD5, CD20, and CD23. Cell size was variably enlarged and CD71 positive, otherwise known as transferrin receptor 1, indicating the mediation of iron transport into cells of erythroid lineage that is necessary for proliferation.¹ Bone marrow core biopsy did not identify features of bone marrow involvement by the lymphoma. Based on these results, the patient was diagnosed with systemic B-cell follicular lymphoma grade 3b stage IIIA. Oncology initiated a systemic chemotherapy regimen with obinutuzumab, cyclophosphamide, doxorubicin hydrochloride (hydroxydaunorubicin), vincristine sulfate, and prednisone. 

Skin involvement in B-cell follicular lymphoma can be primary or secondary. Although all subtypes of BCL can have secondary cutaneous involvement, it is most common in advanced-stage disease (stages III or IV).² Cutaneous manifestations of primary cutaneous follicle-center lymphoma (PCFCL) and systemic/nodal follicular lymphoma secondarily involving the skin can be difficult to distinguish clinically and histopathologically; both appear as solitary or grouped plaques and nodules most commonly on the head, neck, or trunk, and rarely on the legs.³ Although the pathologic features of these two diagnoses can seem almost identical, it is important to differentiate them due to their differing prognosis and management. Patients with follicular lymphoma involving the skin are more likely than those with PCFCL to develop lymphadenopathy and B symptoms.³ Primary cutaneous follicle-center lymphoma also generally runs an indolent course and requires local therapy, while secondary involvement of the skin due to systemic/nodal follicular lymphoma has a worse prognosis and requires systemic chemotherapy treatment.⁴ 

Immunohistochemical markers are the most helpful tool used to distinguish PCFCL from systemic/nodal follicular lymphoma involving the skin. Tumors of B-cell origin are expected to express associated B-cell markers such as CD20, CD79a, and PAX5²; BCL-6, a marker of germinal center cells, also is expected to stain positive.² CD10 is positive in a majority of cases with a follicular growth pattern, while those with a diffuse pattern of growth may have a negative stain.² The most valuable histopathologic indicator differentiating primary and secondary skin involvement is the intensity of BCL-2 expression.⁵ The prognostic significance of the t(14;18)/IgH-BCL2 rearrangement is controversial, with rearrangement identified in more than 75% of systemic/nodal follicular lymphoma cases and less commonly found in PCFCL, with one report arguing an incidence ranging from 1% to 40%.⁵ 

A comprehensive history and physical examination are necessary to develop a differential diagnosis. Our patient's lower leg edema and extensive medical history made the diagnosis more complicated. Pitting edema was present on physical examination, making elephantiasis nostras verrucosa less likely, as it would instead present with nonpitting edema and a woody feel.⁶ Our patient did not have epidemiologic exposure to filariasis through foreign travel and did not present with any classic signs or symptoms of lymphatic filariasis, such as fever, eosinophilia, chyluria, or hydrocele.⁷ Although a negative history of HIV makes Kaposi sarcoma and bacillary angiomatosis less likely diagnoses, a biopsy would be useful to rule out these conditions. Positive inguinal lymphadenopathy present on physical examination may have contributed to lymphatic flow obstruction leading to the leg lymphedema in our patient. 

To the Editor:

A 7-day-old full-term infant presented to the neonatal intensive care unit with poor feeding and altered consciousness. She was born at 39 weeks and 3 days to a gravida 1 mother with a pregnancy history complicated by maternal chorioamnionitis and gestational diabetes. During labor, nonreassuring fetal heart tones and arrest of labor prompted an uncomplicated cesarean delivery with normal Apgar scores at birth. The infant’s family history revealed only beta thalassemia minor in her father. At 5 to 7 days of life, the mother noted difficulty with feeding and poor latch along with lethargy and depressed consciousness in the infant.

Upon arrival to the neonatal intensive care unit, the infant was noted to have rhythmic lip-smacking behavior, intermittent nystagmus, mild hypotonia, and clonic movements of the left upper extremity. An electroencephalogram was markedly abnormal, capturing multiple seizures in the bilateral cortical hemispheres. She was loaded with phenobarbital with no further seizure activity. Brain magnetic resonance imaging revealed innumerable punctate foci of restricted diffusion with corresponding punctate hemorrhage within the frontal and parietal white matter, as well as cortical diffusion restriction within the occipital lobe, inferior temporal lobe, bilateral thalami, and corpus callosum (Figure 1). An exhaustive infectious workup also was completed and was unremarkable, though she was treated with broad-spectrum antimicrobials, including intravenous acyclovir.

Incontinentia pigmenti, also known as Bloch-Sulzberger syndrome, is a rare multisystem neuroectodermal disorder, primarily affecting the skin, central nervous system (CNS), and retinas. The disorder can be inherited in an X-linked dominant fashion and appears almost exclusively in women with typical in utero lethality seen in males. Most affected individuals have a sporadic, or de novo, mutation, which was likely the case in our patient given that her mother demonstrated no signs or symptoms.¹ The pathogenesis of disease is a defect at chromosome Xq28 that is a region encoding the nuclear factor–κB essential modulator, IKBKG. Absence or mutation of IKBKG in IP results in failure to activate nuclear factor–κB and leaves cells vulnerable to cytokine-mediated apoptosis, especially after exposure to tumor necrosis factor α.²

Clinical manifestations of IP are present at or soon after birth. The cutaneous findings of this disorder are classically described as a step-wise progression through 4 distinct stages: (1) a linear and/or whorled vesicular eruption predominantly on the extremities at birth or within the first few weeks of life; (2) thickened linear or whorled verrucous plaques; (3) hyperpigmented streaks and whorls that may or may not correspond with prior affected areas that may resolve by adolescence; and (4) hypopigmented, possibly atrophic plaques on the extremities that may persist lifelong. Importantly, not every patient will experience each of these stages. Overlap can occur, and the time course of each stage is highly variable. Other ectodermal manifestations include dental abnormalities such as small, misshaped, or missing teeth; alopecia; and nail abnormalities. Ocular abnormalities associated with IP primarily occur in the retina, including vascular occlusion, neovascularization, hemorrhages, foveal abnormalities, as well as exudative and tractional detachments.^3,4

It is crucial to recognize CNS anomalies in association with the cutaneous findings of IP, as CNS pathology can be severe with profound developmental implications. Central nervous system findings have been noted to correlate with the appearance of the vesicular stage of IP. A high index of suspicion is needed, as the disease can demonstrate progression within a short time.^5-8 The most frequent anomalies include seizures, motor impairment, intellectual disability, and microcephaly.^9,10 Some of the most commonly identified CNS lesions on imaging include necrosis or brain infarcts, atrophy, and lesions of the corpus callosum.⁷

The pathogenesis of observed CNS changes in IP is not well understood. There have been numerous proposals of a vascular mechanism, and a microangiopathic process appears to be most plausible. Mutations in IKBKG may result in interruption of signaling via vascular endothelial growth factor receptor 3 with a consequent impact on angiogenesis, supporting a vascular mechanism. Additionally, mutations in IKBKG lead to activation of eotaxin, an eosinophil-selective chemokine.⁹ Eotaxin activation results in eosinophilic degranulation that mediates the classic eosinophilic infiltrate seen in the classic skin histology of IP. Additionally, it has been shown that eotaxin is strongly expressed by endothelial cells in IP, and more abundant eosinophil degranulation may play a role in mediating vaso-occlusion.⁷ Other studies have found that the highest expression level of the IKBKG gene is in the CNS, potentially explaining the extensive imaging findings of hemorrhage and diffusion restriction in our patient. These features likely are attributable to apoptosis of cells possessing the mutated IKBKG gene.^9-11

To the Editor:

A 7-day-old full-term infant presented to the neonatal intensive care unit with poor feeding and altered consciousness. She was born at 39 weeks and 3 days to a gravida 1 mother with a pregnancy history complicated by maternal chorioamnionitis and gestational diabetes. During labor, nonreassuring fetal heart tones and arrest of labor prompted an uncomplicated cesarean delivery with normal Apgar scores at birth. The infant’s family history revealed only beta thalassemia minor in her father. At 5 to 7 days of life, the mother noted difficulty with feeding and poor latch along with lethargy and depressed consciousness in the infant.

Upon arrival to the neonatal intensive care unit, the infant was noted to have rhythmic lip-smacking behavior, intermittent nystagmus, mild hypotonia, and clonic movements of the left upper extremity. An electroencephalogram was markedly abnormal, capturing multiple seizures in the bilateral cortical hemispheres. She was loaded with phenobarbital with no further seizure activity. Brain magnetic resonance imaging revealed innumerable punctate foci of restricted diffusion with corresponding punctate hemorrhage within the frontal and parietal white matter, as well as cortical diffusion restriction within the occipital lobe, inferior temporal lobe, bilateral thalami, and corpus callosum (Figure 1). An exhaustive infectious workup also was completed and was unremarkable, though she was treated with broad-spectrum antimicrobials, including intravenous acyclovir.

Incontinentia pigmenti, also known as Bloch-Sulzberger syndrome, is a rare multisystem neuroectodermal disorder, primarily affecting the skin, central nervous system (CNS), and retinas. The disorder can be inherited in an X-linked dominant fashion and appears almost exclusively in women with typical in utero lethality seen in males. Most affected individuals have a sporadic, or de novo, mutation, which was likely the case in our patient given that her mother demonstrated no signs or symptoms.¹ The pathogenesis of disease is a defect at chromosome Xq28 that is a region encoding the nuclear factor–κB essential modulator, IKBKG. Absence or mutation of IKBKG in IP results in failure to activate nuclear factor–κB and leaves cells vulnerable to cytokine-mediated apoptosis, especially after exposure to tumor necrosis factor α.²

Clinical manifestations of IP are present at or soon after birth. The cutaneous findings of this disorder are classically described as a step-wise progression through 4 distinct stages: (1) a linear and/or whorled vesicular eruption predominantly on the extremities at birth or within the first few weeks of life; (2) thickened linear or whorled verrucous plaques; (3) hyperpigmented streaks and whorls that may or may not correspond with prior affected areas that may resolve by adolescence; and (4) hypopigmented, possibly atrophic plaques on the extremities that may persist lifelong. Importantly, not every patient will experience each of these stages. Overlap can occur, and the time course of each stage is highly variable. Other ectodermal manifestations include dental abnormalities such as small, misshaped, or missing teeth; alopecia; and nail abnormalities. Ocular abnormalities associated with IP primarily occur in the retina, including vascular occlusion, neovascularization, hemorrhages, foveal abnormalities, as well as exudative and tractional detachments.^3,4

It is crucial to recognize CNS anomalies in association with the cutaneous findings of IP, as CNS pathology can be severe with profound developmental implications. Central nervous system findings have been noted to correlate with the appearance of the vesicular stage of IP. A high index of suspicion is needed, as the disease can demonstrate progression within a short time.^5-8 The most frequent anomalies include seizures, motor impairment, intellectual disability, and microcephaly.^9,10 Some of the most commonly identified CNS lesions on imaging include necrosis or brain infarcts, atrophy, and lesions of the corpus callosum.⁷

The pathogenesis of observed CNS changes in IP is not well understood. There have been numerous proposals of a vascular mechanism, and a microangiopathic process appears to be most plausible. Mutations in IKBKG may result in interruption of signaling via vascular endothelial growth factor receptor 3 with a consequent impact on angiogenesis, supporting a vascular mechanism. Additionally, mutations in IKBKG lead to activation of eotaxin, an eosinophil-selective chemokine.⁹ Eotaxin activation results in eosinophilic degranulation that mediates the classic eosinophilic infiltrate seen in the classic skin histology of IP. Additionally, it has been shown that eotaxin is strongly expressed by endothelial cells in IP, and more abundant eosinophil degranulation may play a role in mediating vaso-occlusion.⁷ Other studies have found that the highest expression level of the IKBKG gene is in the CNS, potentially explaining the extensive imaging findings of hemorrhage and diffusion restriction in our patient. These features likely are attributable to apoptosis of cells possessing the mutated IKBKG gene.^9-11

To the Editor:

A 7-day-old full-term infant presented to the neonatal intensive care unit with poor feeding and altered consciousness. She was born at 39 weeks and 3 days to a gravida 1 mother with a pregnancy history complicated by maternal chorioamnionitis and gestational diabetes. During labor, nonreassuring fetal heart tones and arrest of labor prompted an uncomplicated cesarean delivery with normal Apgar scores at birth. The infant’s family history revealed only beta thalassemia minor in her father. At 5 to 7 days of life, the mother noted difficulty with feeding and poor latch along with lethargy and depressed consciousness in the infant.

Upon arrival to the neonatal intensive care unit, the infant was noted to have rhythmic lip-smacking behavior, intermittent nystagmus, mild hypotonia, and clonic movements of the left upper extremity. An electroencephalogram was markedly abnormal, capturing multiple seizures in the bilateral cortical hemispheres. She was loaded with phenobarbital with no further seizure activity. Brain magnetic resonance imaging revealed innumerable punctate foci of restricted diffusion with corresponding punctate hemorrhage within the frontal and parietal white matter, as well as cortical diffusion restriction within the occipital lobe, inferior temporal lobe, bilateral thalami, and corpus callosum (Figure 1). An exhaustive infectious workup also was completed and was unremarkable, though she was treated with broad-spectrum antimicrobials, including intravenous acyclovir.

Incontinentia pigmenti, also known as Bloch-Sulzberger syndrome, is a rare multisystem neuroectodermal disorder, primarily affecting the skin, central nervous system (CNS), and retinas. The disorder can be inherited in an X-linked dominant fashion and appears almost exclusively in women with typical in utero lethality seen in males. Most affected individuals have a sporadic, or de novo, mutation, which was likely the case in our patient given that her mother demonstrated no signs or symptoms.¹ The pathogenesis of disease is a defect at chromosome Xq28 that is a region encoding the nuclear factor–κB essential modulator, IKBKG. Absence or mutation of IKBKG in IP results in failure to activate nuclear factor–κB and leaves cells vulnerable to cytokine-mediated apoptosis, especially after exposure to tumor necrosis factor α.²

Clinical manifestations of IP are present at or soon after birth. The cutaneous findings of this disorder are classically described as a step-wise progression through 4 distinct stages: (1) a linear and/or whorled vesicular eruption predominantly on the extremities at birth or within the first few weeks of life; (2) thickened linear or whorled verrucous plaques; (3) hyperpigmented streaks and whorls that may or may not correspond with prior affected areas that may resolve by adolescence; and (4) hypopigmented, possibly atrophic plaques on the extremities that may persist lifelong. Importantly, not every patient will experience each of these stages. Overlap can occur, and the time course of each stage is highly variable. Other ectodermal manifestations include dental abnormalities such as small, misshaped, or missing teeth; alopecia; and nail abnormalities. Ocular abnormalities associated with IP primarily occur in the retina, including vascular occlusion, neovascularization, hemorrhages, foveal abnormalities, as well as exudative and tractional detachments.^3,4

It is crucial to recognize CNS anomalies in association with the cutaneous findings of IP, as CNS pathology can be severe with profound developmental implications. Central nervous system findings have been noted to correlate with the appearance of the vesicular stage of IP. A high index of suspicion is needed, as the disease can demonstrate progression within a short time.^5-8 The most frequent anomalies include seizures, motor impairment, intellectual disability, and microcephaly.^9,10 Some of the most commonly identified CNS lesions on imaging include necrosis or brain infarcts, atrophy, and lesions of the corpus callosum.⁷

The pathogenesis of observed CNS changes in IP is not well understood. There have been numerous proposals of a vascular mechanism, and a microangiopathic process appears to be most plausible. Mutations in IKBKG may result in interruption of signaling via vascular endothelial growth factor receptor 3 with a consequent impact on angiogenesis, supporting a vascular mechanism. Additionally, mutations in IKBKG lead to activation of eotaxin, an eosinophil-selective chemokine.⁹ Eotaxin activation results in eosinophilic degranulation that mediates the classic eosinophilic infiltrate seen in the classic skin histology of IP. Additionally, it has been shown that eotaxin is strongly expressed by endothelial cells in IP, and more abundant eosinophil degranulation may play a role in mediating vaso-occlusion.⁷ Other studies have found that the highest expression level of the IKBKG gene is in the CNS, potentially explaining the extensive imaging findings of hemorrhage and diffusion restriction in our patient. These features likely are attributable to apoptosis of cells possessing the mutated IKBKG gene.^9-11

Breast cancer is the second most common malignancy in women (after primary skin cancer) and is the second leading cause of cancer-related death in this population. In 2020, the American Cancer Society reported an estimated 276,480 new breast cancer diagnoses and 42,170 breast cancer–related deaths.¹ Despite the fact that routine screening with mammography and sonography is standard, the incidence of advanced breast cancer at the time of diagnosis has remained stable over time, suggesting that life-threatening breast cancers are not being caught at an earlier stage. The number of breast cancers with distant metastases at the time of diagnosis also has not decreased.² Therefore, although screening tests are valuable, they are imperfect and not without limitations.

Cutaneous metastasis is defined as the spread of malignant cells from an internal neoplasm to the skin, which can occur either by contiguous invasion or by distant metastasis through hematogenous or lymphatic routes.³ The diagnosis of cutaneous metastasis requires a high index of suspicion on the part of the clinician.⁴ Of the various internal malignancies in women, breast cancer most frequently results in metastasis to the skin,⁵ with up to 24% of patients with metastatic breast cancer developing cutaneous lesions.⁶

In recent years, there have been multiple reports of skin lesions prompting the diagnosis of a previously unknown breast cancer. In a study by Lookingbill et al,⁶ 6.3% of patients with breast cancer presented with cutaneous involvement at the time of diagnosis, with 3.5% having skin symptoms as the presenting sign. Although there have been studies analyzing cutaneous metastasis from various internal malignancies, none thus far have focused on cutaneous metastasis as a presenting sign of breast cancer. This systematic review aimed to highlight the diverse clinical presentations of cutaneous metastatic breast cancer and their clinical implications.

Methods

Study Selection
This study utilized the PRISMA guidelines for systematic reviews.⁷ A review of the literature was conducted using the following databases: MEDLINE/PubMed, EMBASE, Cochrane library, CINAHL, and EBSCO.

Search Strategy and Analysis
We completed our search of each of the databases on December 16, 2017, using the phrases cutaneous metastasis and breast cancer to find relevant case reports and retrospective studies. Three authors (C.J., S.R., and M.A.) manually reviewed the resulting abstracts. If an abstract did not include enough information to determine inclusion, the full-text version was reviewed by 2 of the authors (C.J. and S.R.). Two of the authors (C.J. and M.A.) also assessed each source for relevancy and included the articles deemed eligible (Figure 1).

For a retrospective review to be included, it must have specified the number of breast cancer cases and the number of cutaneous metastases presenting initially or simultaneously to the breast cancer diagnosis. Bansal et al⁸ defined a simultaneous diagnosis as a skin lesion presenting with other concerns associated with the primary malignancy.

Results

The initial search of MEDLINE/PubMed, EMBASE, Cochrane library, CINAHL, and EBSCO yielded a total of 722 articles. Seven other articles found separately while undergoing our initial research were added to this total. Abstracts were manually screened, with 657 articles discarded after failing to meet the predetermined inclusion criteria. After removal of 25 duplicate articles, the full text of the remaining 47 articles were reviewed, leading to the elimination of an additional 11 articles that did not meet the necessary criteria. This resulted in 36 articles (Figure 1), including 27 individual case reports (Table 1) and 9 retrospective reviews (Table 2). Approximately 13.7% of patients in the 9 retrospective reviews presented with a skin lesion before or simultaneous to the diagnosis of breast cancer (Figure 2).

Forty-one percent (17/41) of the patients with cutaneous metastasis as a presenting feature of their breast cancer fell outside the age range for breast cancer screening recommended by the US Preventive Services Task Force,⁴² with 24% of the patients younger than 50 years and 17% older than 74 years (Figure 3).

Comment

Our systematic review demonstrated that cutaneous lesions may be the first clinical manifestation of an undetected primary malignancy.⁴⁰ These lesions often occur on the chest but may involve the face, abdomen, or extremities. Although asymptomatic erythematous nodules and plaques are the most common clinical presentations, lesions may be tender or pruritic or may even resemble benign skin conditions, including dermatitis, cellulitis, urticaria, and papulovesicular eruptions, causing them to go unrecognized.

Nevertheless, cutaneous metastasis of a visceral malignancy generally is observed late in the disease course, often following the diagnosis of a primary malignancy.¹⁴ Breast cancer is the most common internal malignancy to feature cutaneous spread, with the largest case series revealing a 23.9% rate of cutaneous metastases in females with breast carcinoma.⁶ Because of its proximity, the chest wall is the most common location for cutaneous lesions of metastatic breast cancer.

Malignant cells from a primary breast tumor may spread to the skin via lymphatic, hematogenous, or contiguous tissue dissemination, as well as iatrogenically through direct implantation during surgical procedures.³ The mechanism of neoplasm spread may likewise influence the clinical appearance of the resulting lesions. The localized lymphedema with a peau d’orange appearance of inflammatory metastatic breast carcinoma or the erythematous plaques of carcinoma erysipeloides are caused by embolized tumor cells obstructing dermal lymphatic vessels.^3,11 On the other hand, the indurated erythematous plaques of carcinoma en cuirasse are caused by diffuse cutaneous and subcutaneous infiltration of tumor cells that also may be associated with marked reduction in breast volume.³

A primary breast cancer is classically diagnosed with a combination of clinical breast examination, radiologic imaging (ultrasound, mammogram, breast magnetic resonance imaging, or computed tomography), and fine-needle aspiration or lesional biopsy with histopathology.⁹ Given that in 20% of metastasized breast cancers the primary tumor may not be identified, a negative breast examination and imaging do not rule out breast cancer, especially if cutaneous biopsy reveals a primary malignancy.⁴³ Histopathology and immunohistochemistry can thereby confirm the presence of metastatic cutaneous lesions and help characterize the breast cancer type involved, with adenocarcinomas being most commonly implicated.²⁸ Although both ductal and lobular adenocarcinomas stain positive for cytokeratin 7, estrogen receptor, progesterone receptor, gross cystic disease fluid protein 15, carcinoembryonic antigen, and mammaglobin, only the former shows positivity for e-cadherin markers.³ Conversely, inflammatory carcinoma stains positive for CD31 and podoplanin, telangiectatic carcinoma stains positive for CD31, and mammary Paget disease stains positive for cytokeratin 7 and mucin 1, cell surface associated.³ Apart from cutaneous biopsy, fine-needle aspiration cytology can likewise provide a simple and rapid method of diagnosis with high sensitivity and specificity.¹⁴

Conclusion

Although cutaneous metastasis as the presenting sign of a breast malignancy is rare, a high index of suspicion should be exercised when encountering rapid-onset, out-of-place nodules or plaques in female patients, particularly nodules or plaques presenting on the chest.

Breast cancer is the second most common malignancy in women (after primary skin cancer) and is the second leading cause of cancer-related death in this population. In 2020, the American Cancer Society reported an estimated 276,480 new breast cancer diagnoses and 42,170 breast cancer–related deaths.¹ Despite the fact that routine screening with mammography and sonography is standard, the incidence of advanced breast cancer at the time of diagnosis has remained stable over time, suggesting that life-threatening breast cancers are not being caught at an earlier stage. The number of breast cancers with distant metastases at the time of diagnosis also has not decreased.² Therefore, although screening tests are valuable, they are imperfect and not without limitations.

Cutaneous metastasis is defined as the spread of malignant cells from an internal neoplasm to the skin, which can occur either by contiguous invasion or by distant metastasis through hematogenous or lymphatic routes.³ The diagnosis of cutaneous metastasis requires a high index of suspicion on the part of the clinician.⁴ Of the various internal malignancies in women, breast cancer most frequently results in metastasis to the skin,⁵ with up to 24% of patients with metastatic breast cancer developing cutaneous lesions.⁶

In recent years, there have been multiple reports of skin lesions prompting the diagnosis of a previously unknown breast cancer. In a study by Lookingbill et al,⁶ 6.3% of patients with breast cancer presented with cutaneous involvement at the time of diagnosis, with 3.5% having skin symptoms as the presenting sign. Although there have been studies analyzing cutaneous metastasis from various internal malignancies, none thus far have focused on cutaneous metastasis as a presenting sign of breast cancer. This systematic review aimed to highlight the diverse clinical presentations of cutaneous metastatic breast cancer and their clinical implications.

Methods

Study Selection
This study utilized the PRISMA guidelines for systematic reviews.⁷ A review of the literature was conducted using the following databases: MEDLINE/PubMed, EMBASE, Cochrane library, CINAHL, and EBSCO.

Search Strategy and Analysis
We completed our search of each of the databases on December 16, 2017, using the phrases cutaneous metastasis and breast cancer to find relevant case reports and retrospective studies. Three authors (C.J., S.R., and M.A.) manually reviewed the resulting abstracts. If an abstract did not include enough information to determine inclusion, the full-text version was reviewed by 2 of the authors (C.J. and S.R.). Two of the authors (C.J. and M.A.) also assessed each source for relevancy and included the articles deemed eligible (Figure 1).

For a retrospective review to be included, it must have specified the number of breast cancer cases and the number of cutaneous metastases presenting initially or simultaneously to the breast cancer diagnosis. Bansal et al⁸ defined a simultaneous diagnosis as a skin lesion presenting with other concerns associated with the primary malignancy.

Results

The initial search of MEDLINE/PubMed, EMBASE, Cochrane library, CINAHL, and EBSCO yielded a total of 722 articles. Seven other articles found separately while undergoing our initial research were added to this total. Abstracts were manually screened, with 657 articles discarded after failing to meet the predetermined inclusion criteria. After removal of 25 duplicate articles, the full text of the remaining 47 articles were reviewed, leading to the elimination of an additional 11 articles that did not meet the necessary criteria. This resulted in 36 articles (Figure 1), including 27 individual case reports (Table 1) and 9 retrospective reviews (Table 2). Approximately 13.7% of patients in the 9 retrospective reviews presented with a skin lesion before or simultaneous to the diagnosis of breast cancer (Figure 2).

Forty-one percent (17/41) of the patients with cutaneous metastasis as a presenting feature of their breast cancer fell outside the age range for breast cancer screening recommended by the US Preventive Services Task Force,⁴² with 24% of the patients younger than 50 years and 17% older than 74 years (Figure 3).

Comment

Our systematic review demonstrated that cutaneous lesions may be the first clinical manifestation of an undetected primary malignancy.⁴⁰ These lesions often occur on the chest but may involve the face, abdomen, or extremities. Although asymptomatic erythematous nodules and plaques are the most common clinical presentations, lesions may be tender or pruritic or may even resemble benign skin conditions, including dermatitis, cellulitis, urticaria, and papulovesicular eruptions, causing them to go unrecognized.

Nevertheless, cutaneous metastasis of a visceral malignancy generally is observed late in the disease course, often following the diagnosis of a primary malignancy.¹⁴ Breast cancer is the most common internal malignancy to feature cutaneous spread, with the largest case series revealing a 23.9% rate of cutaneous metastases in females with breast carcinoma.⁶ Because of its proximity, the chest wall is the most common location for cutaneous lesions of metastatic breast cancer.

Malignant cells from a primary breast tumor may spread to the skin via lymphatic, hematogenous, or contiguous tissue dissemination, as well as iatrogenically through direct implantation during surgical procedures.³ The mechanism of neoplasm spread may likewise influence the clinical appearance of the resulting lesions. The localized lymphedema with a peau d’orange appearance of inflammatory metastatic breast carcinoma or the erythematous plaques of carcinoma erysipeloides are caused by embolized tumor cells obstructing dermal lymphatic vessels.^3,11 On the other hand, the indurated erythematous plaques of carcinoma en cuirasse are caused by diffuse cutaneous and subcutaneous infiltration of tumor cells that also may be associated with marked reduction in breast volume.³

A primary breast cancer is classically diagnosed with a combination of clinical breast examination, radiologic imaging (ultrasound, mammogram, breast magnetic resonance imaging, or computed tomography), and fine-needle aspiration or lesional biopsy with histopathology.⁹ Given that in 20% of metastasized breast cancers the primary tumor may not be identified, a negative breast examination and imaging do not rule out breast cancer, especially if cutaneous biopsy reveals a primary malignancy.⁴³ Histopathology and immunohistochemistry can thereby confirm the presence of metastatic cutaneous lesions and help characterize the breast cancer type involved, with adenocarcinomas being most commonly implicated.²⁸ Although both ductal and lobular adenocarcinomas stain positive for cytokeratin 7, estrogen receptor, progesterone receptor, gross cystic disease fluid protein 15, carcinoembryonic antigen, and mammaglobin, only the former shows positivity for e-cadherin markers.³ Conversely, inflammatory carcinoma stains positive for CD31 and podoplanin, telangiectatic carcinoma stains positive for CD31, and mammary Paget disease stains positive for cytokeratin 7 and mucin 1, cell surface associated.³ Apart from cutaneous biopsy, fine-needle aspiration cytology can likewise provide a simple and rapid method of diagnosis with high sensitivity and specificity.¹⁴

Conclusion

Although cutaneous metastasis as the presenting sign of a breast malignancy is rare, a high index of suspicion should be exercised when encountering rapid-onset, out-of-place nodules or plaques in female patients, particularly nodules or plaques presenting on the chest.

Breast cancer is the second most common malignancy in women (after primary skin cancer) and is the second leading cause of cancer-related death in this population. In 2020, the American Cancer Society reported an estimated 276,480 new breast cancer diagnoses and 42,170 breast cancer–related deaths.¹ Despite the fact that routine screening with mammography and sonography is standard, the incidence of advanced breast cancer at the time of diagnosis has remained stable over time, suggesting that life-threatening breast cancers are not being caught at an earlier stage. The number of breast cancers with distant metastases at the time of diagnosis also has not decreased.² Therefore, although screening tests are valuable, they are imperfect and not without limitations.

Cutaneous metastasis is defined as the spread of malignant cells from an internal neoplasm to the skin, which can occur either by contiguous invasion or by distant metastasis through hematogenous or lymphatic routes.³ The diagnosis of cutaneous metastasis requires a high index of suspicion on the part of the clinician.⁴ Of the various internal malignancies in women, breast cancer most frequently results in metastasis to the skin,⁵ with up to 24% of patients with metastatic breast cancer developing cutaneous lesions.⁶

In recent years, there have been multiple reports of skin lesions prompting the diagnosis of a previously unknown breast cancer. In a study by Lookingbill et al,⁶ 6.3% of patients with breast cancer presented with cutaneous involvement at the time of diagnosis, with 3.5% having skin symptoms as the presenting sign. Although there have been studies analyzing cutaneous metastasis from various internal malignancies, none thus far have focused on cutaneous metastasis as a presenting sign of breast cancer. This systematic review aimed to highlight the diverse clinical presentations of cutaneous metastatic breast cancer and their clinical implications.

Methods

Study Selection
This study utilized the PRISMA guidelines for systematic reviews.⁷ A review of the literature was conducted using the following databases: MEDLINE/PubMed, EMBASE, Cochrane library, CINAHL, and EBSCO.

Search Strategy and Analysis
We completed our search of each of the databases on December 16, 2017, using the phrases cutaneous metastasis and breast cancer to find relevant case reports and retrospective studies. Three authors (C.J., S.R., and M.A.) manually reviewed the resulting abstracts. If an abstract did not include enough information to determine inclusion, the full-text version was reviewed by 2 of the authors (C.J. and S.R.). Two of the authors (C.J. and M.A.) also assessed each source for relevancy and included the articles deemed eligible (Figure 1).

For a retrospective review to be included, it must have specified the number of breast cancer cases and the number of cutaneous metastases presenting initially or simultaneously to the breast cancer diagnosis. Bansal et al⁸ defined a simultaneous diagnosis as a skin lesion presenting with other concerns associated with the primary malignancy.

Results

The initial search of MEDLINE/PubMed, EMBASE, Cochrane library, CINAHL, and EBSCO yielded a total of 722 articles. Seven other articles found separately while undergoing our initial research were added to this total. Abstracts were manually screened, with 657 articles discarded after failing to meet the predetermined inclusion criteria. After removal of 25 duplicate articles, the full text of the remaining 47 articles were reviewed, leading to the elimination of an additional 11 articles that did not meet the necessary criteria. This resulted in 36 articles (Figure 1), including 27 individual case reports (Table 1) and 9 retrospective reviews (Table 2). Approximately 13.7% of patients in the 9 retrospective reviews presented with a skin lesion before or simultaneous to the diagnosis of breast cancer (Figure 2).

Forty-one percent (17/41) of the patients with cutaneous metastasis as a presenting feature of their breast cancer fell outside the age range for breast cancer screening recommended by the US Preventive Services Task Force,⁴² with 24% of the patients younger than 50 years and 17% older than 74 years (Figure 3).

Comment

Our systematic review demonstrated that cutaneous lesions may be the first clinical manifestation of an undetected primary malignancy.⁴⁰ These lesions often occur on the chest but may involve the face, abdomen, or extremities. Although asymptomatic erythematous nodules and plaques are the most common clinical presentations, lesions may be tender or pruritic or may even resemble benign skin conditions, including dermatitis, cellulitis, urticaria, and papulovesicular eruptions, causing them to go unrecognized.

Nevertheless, cutaneous metastasis of a visceral malignancy generally is observed late in the disease course, often following the diagnosis of a primary malignancy.¹⁴ Breast cancer is the most common internal malignancy to feature cutaneous spread, with the largest case series revealing a 23.9% rate of cutaneous metastases in females with breast carcinoma.⁶ Because of its proximity, the chest wall is the most common location for cutaneous lesions of metastatic breast cancer.

Malignant cells from a primary breast tumor may spread to the skin via lymphatic, hematogenous, or contiguous tissue dissemination, as well as iatrogenically through direct implantation during surgical procedures.³ The mechanism of neoplasm spread may likewise influence the clinical appearance of the resulting lesions. The localized lymphedema with a peau d’orange appearance of inflammatory metastatic breast carcinoma or the erythematous plaques of carcinoma erysipeloides are caused by embolized tumor cells obstructing dermal lymphatic vessels.^3,11 On the other hand, the indurated erythematous plaques of carcinoma en cuirasse are caused by diffuse cutaneous and subcutaneous infiltration of tumor cells that also may be associated with marked reduction in breast volume.³

A primary breast cancer is classically diagnosed with a combination of clinical breast examination, radiologic imaging (ultrasound, mammogram, breast magnetic resonance imaging, or computed tomography), and fine-needle aspiration or lesional biopsy with histopathology.⁹ Given that in 20% of metastasized breast cancers the primary tumor may not be identified, a negative breast examination and imaging do not rule out breast cancer, especially if cutaneous biopsy reveals a primary malignancy.⁴³ Histopathology and immunohistochemistry can thereby confirm the presence of metastatic cutaneous lesions and help characterize the breast cancer type involved, with adenocarcinomas being most commonly implicated.²⁸ Although both ductal and lobular adenocarcinomas stain positive for cytokeratin 7, estrogen receptor, progesterone receptor, gross cystic disease fluid protein 15, carcinoembryonic antigen, and mammaglobin, only the former shows positivity for e-cadherin markers.³ Conversely, inflammatory carcinoma stains positive for CD31 and podoplanin, telangiectatic carcinoma stains positive for CD31, and mammary Paget disease stains positive for cytokeratin 7 and mucin 1, cell surface associated.³ Apart from cutaneous biopsy, fine-needle aspiration cytology can likewise provide a simple and rapid method of diagnosis with high sensitivity and specificity.¹⁴

Conclusion

Although cutaneous metastasis as the presenting sign of a breast malignancy is rare, a high index of suspicion should be exercised when encountering rapid-onset, out-of-place nodules or plaques in female patients, particularly nodules or plaques presenting on the chest.