Cutis

To the Editor:

Atopic diseases, specifically atopic dermatitis (AD) and alopecia areata (AA), are at the forefront of a new era in dermatology involving molecular-directed therapy. Dupilumab is one specific example, having received US Food and Drug Administration approval in March 2017 for the treatment of adults with moderate to severe AD.¹ It currently is being investigated for use in pediatric AD. The most commonly reported side effects associated with the use of dupilumab include headaches, conjunctivitis, keratitis, blepharitis, nasopharyngitis, and injection-site reactions.² We discuss a case of hair regrowth in a patient who was previously diagnosed with AA after treatment with dupilumab for refractory AD.

A 65-year-old White man presented with a history of AD since childhood. Additional medical history included hyperlipidemia; herpes simplex virus infection; asthma; and a diagnosis of AA 6 years prior, which eventually progressed to alopecia universalis. Physical examination demonstrated scattered erythematous lichenified plaques with excoriations involving the arms, legs, and trunk. The patient’s face and scalp were spared of lesions. Complete loss of body hair including the eyelashes and eyebrows also was noted, which was consistent with alopecia universalis.

The patient was started on dupilumab for refractory AD after multiple courses of topical and systemic steroids failed. Prior treatment for AD did not include immunosuppressive or light therapy. The standard dosage of dupilumab was administered, which consisted of a 600-mg subcutaneous loading dose, followed by 300 mg every 2 weeks. There was no concurrent topical corticosteroid or topical calcineurin inhibitor prescribed. After 1 month of treatment with dupilumab, near-complete resolution of the patient’s AD was noted, and after 10 months of treatment, the patient experienced regrowth of the eyelashes, terminal hairs of the beard area (Figure), and vellus hairs of the eyebrows. This hair regrowth persists today with continued dupilumab treatment, and the patient has experienced no additional side effects.

Multiple retrospective and meta-analysis studies have demonstrated a high occurrence of AD comorbid with AA, which strongly suggests a common pathogenesis.^3,4 Atopic dermatitis is an inflammatory skin disease mediated by IL-4, IL-5, and IL-13 of the helper T-cell type 2 (T_H2) pathway.¹ Dupilumab is a human monoclonal antibody that binds to IL-4Rα, which also is found in IL-13 receptors. Dupilumab prevents T_H2 pathway-related downstream signaling effects of both cytokines. Although this effect was originally utilized to suppress the T_H2-mediated signaling in AD, our patient and others have demonstrated successful hair regrowth with dupilumab, which likely stems from a similar T_H2-related antagonism in AA.^5,6

The cause of AA is unknown, but IL-4 and IL-13 of the T_H2 pathway have been implicated, which renders support for the therapeutic effect of dupilumab in the treatment of AA. Scalp samples of patients with AA have demonstrated upregulation of T_H2, helper T-cell type 1 (T_H1), and IL-23 cytokines, suggesting efficacy with the use of anti-T_H2, anti-T_H1, and anti–IL-23 therapies.⁷ Polymerase chain reaction testing performed on serum samples in patients with AA displayed marked elevation of T_H2 cytokines, notably IL-13, which were reduced following intralesional corticosteroid treatment.⁸ It also has been demonstrated that multiple T_H2-related genes contribute to the genetic susceptibility of developing AA, specifically IL-4 and IL-13.^9,10

Prior case reports have shown contradicting effects (dupilumab-induced AA), which are speculated to be caused by a stronger T_H1 response from T_H2 suppression.^11,12 In one report, dupilumab was initiated for AD refractory to multiple topical and oral interventions. New-onset hair loss to the scalp was noted after 18 weeks of therapy. Twenty-six weeks into therapy with dupilumab, full hair regrowth was then reported.¹¹ Despite this report, our patient’s hair regrowth after the use of dupilumab for refractory AD further strengthens support for the use of dupilumab as a potential therapy for alopecia universalis and other lymphocyte-mediated hair loss conditions. However, a large disparity in response time and an overall slower progression of hair regrowth reported in our case separate it from other reports of rapid voluminous hair regrowth.^5,6 Our findings support the potential use of dupilumab in the treatment of patients with AA.

To the Editor:

Atopic diseases, specifically atopic dermatitis (AD) and alopecia areata (AA), are at the forefront of a new era in dermatology involving molecular-directed therapy. Dupilumab is one specific example, having received US Food and Drug Administration approval in March 2017 for the treatment of adults with moderate to severe AD.¹ It currently is being investigated for use in pediatric AD. The most commonly reported side effects associated with the use of dupilumab include headaches, conjunctivitis, keratitis, blepharitis, nasopharyngitis, and injection-site reactions.² We discuss a case of hair regrowth in a patient who was previously diagnosed with AA after treatment with dupilumab for refractory AD.

A 65-year-old White man presented with a history of AD since childhood. Additional medical history included hyperlipidemia; herpes simplex virus infection; asthma; and a diagnosis of AA 6 years prior, which eventually progressed to alopecia universalis. Physical examination demonstrated scattered erythematous lichenified plaques with excoriations involving the arms, legs, and trunk. The patient’s face and scalp were spared of lesions. Complete loss of body hair including the eyelashes and eyebrows also was noted, which was consistent with alopecia universalis.

The patient was started on dupilumab for refractory AD after multiple courses of topical and systemic steroids failed. Prior treatment for AD did not include immunosuppressive or light therapy. The standard dosage of dupilumab was administered, which consisted of a 600-mg subcutaneous loading dose, followed by 300 mg every 2 weeks. There was no concurrent topical corticosteroid or topical calcineurin inhibitor prescribed. After 1 month of treatment with dupilumab, near-complete resolution of the patient’s AD was noted, and after 10 months of treatment, the patient experienced regrowth of the eyelashes, terminal hairs of the beard area (Figure), and vellus hairs of the eyebrows. This hair regrowth persists today with continued dupilumab treatment, and the patient has experienced no additional side effects.

Multiple retrospective and meta-analysis studies have demonstrated a high occurrence of AD comorbid with AA, which strongly suggests a common pathogenesis.^3,4 Atopic dermatitis is an inflammatory skin disease mediated by IL-4, IL-5, and IL-13 of the helper T-cell type 2 (T_H2) pathway.¹ Dupilumab is a human monoclonal antibody that binds to IL-4Rα, which also is found in IL-13 receptors. Dupilumab prevents T_H2 pathway-related downstream signaling effects of both cytokines. Although this effect was originally utilized to suppress the T_H2-mediated signaling in AD, our patient and others have demonstrated successful hair regrowth with dupilumab, which likely stems from a similar T_H2-related antagonism in AA.^5,6

The cause of AA is unknown, but IL-4 and IL-13 of the T_H2 pathway have been implicated, which renders support for the therapeutic effect of dupilumab in the treatment of AA. Scalp samples of patients with AA have demonstrated upregulation of T_H2, helper T-cell type 1 (T_H1), and IL-23 cytokines, suggesting efficacy with the use of anti-T_H2, anti-T_H1, and anti–IL-23 therapies.⁷ Polymerase chain reaction testing performed on serum samples in patients with AA displayed marked elevation of T_H2 cytokines, notably IL-13, which were reduced following intralesional corticosteroid treatment.⁸ It also has been demonstrated that multiple T_H2-related genes contribute to the genetic susceptibility of developing AA, specifically IL-4 and IL-13.^9,10

Prior case reports have shown contradicting effects (dupilumab-induced AA), which are speculated to be caused by a stronger T_H1 response from T_H2 suppression.^11,12 In one report, dupilumab was initiated for AD refractory to multiple topical and oral interventions. New-onset hair loss to the scalp was noted after 18 weeks of therapy. Twenty-six weeks into therapy with dupilumab, full hair regrowth was then reported.¹¹ Despite this report, our patient’s hair regrowth after the use of dupilumab for refractory AD further strengthens support for the use of dupilumab as a potential therapy for alopecia universalis and other lymphocyte-mediated hair loss conditions. However, a large disparity in response time and an overall slower progression of hair regrowth reported in our case separate it from other reports of rapid voluminous hair regrowth.^5,6 Our findings support the potential use of dupilumab in the treatment of patients with AA.

To the Editor:

Atopic diseases, specifically atopic dermatitis (AD) and alopecia areata (AA), are at the forefront of a new era in dermatology involving molecular-directed therapy. Dupilumab is one specific example, having received US Food and Drug Administration approval in March 2017 for the treatment of adults with moderate to severe AD.¹ It currently is being investigated for use in pediatric AD. The most commonly reported side effects associated with the use of dupilumab include headaches, conjunctivitis, keratitis, blepharitis, nasopharyngitis, and injection-site reactions.² We discuss a case of hair regrowth in a patient who was previously diagnosed with AA after treatment with dupilumab for refractory AD.

A 65-year-old White man presented with a history of AD since childhood. Additional medical history included hyperlipidemia; herpes simplex virus infection; asthma; and a diagnosis of AA 6 years prior, which eventually progressed to alopecia universalis. Physical examination demonstrated scattered erythematous lichenified plaques with excoriations involving the arms, legs, and trunk. The patient’s face and scalp were spared of lesions. Complete loss of body hair including the eyelashes and eyebrows also was noted, which was consistent with alopecia universalis.

The patient was started on dupilumab for refractory AD after multiple courses of topical and systemic steroids failed. Prior treatment for AD did not include immunosuppressive or light therapy. The standard dosage of dupilumab was administered, which consisted of a 600-mg subcutaneous loading dose, followed by 300 mg every 2 weeks. There was no concurrent topical corticosteroid or topical calcineurin inhibitor prescribed. After 1 month of treatment with dupilumab, near-complete resolution of the patient’s AD was noted, and after 10 months of treatment, the patient experienced regrowth of the eyelashes, terminal hairs of the beard area (Figure), and vellus hairs of the eyebrows. This hair regrowth persists today with continued dupilumab treatment, and the patient has experienced no additional side effects.

Multiple retrospective and meta-analysis studies have demonstrated a high occurrence of AD comorbid with AA, which strongly suggests a common pathogenesis.^3,4 Atopic dermatitis is an inflammatory skin disease mediated by IL-4, IL-5, and IL-13 of the helper T-cell type 2 (T_H2) pathway.¹ Dupilumab is a human monoclonal antibody that binds to IL-4Rα, which also is found in IL-13 receptors. Dupilumab prevents T_H2 pathway-related downstream signaling effects of both cytokines. Although this effect was originally utilized to suppress the T_H2-mediated signaling in AD, our patient and others have demonstrated successful hair regrowth with dupilumab, which likely stems from a similar T_H2-related antagonism in AA.^5,6

The cause of AA is unknown, but IL-4 and IL-13 of the T_H2 pathway have been implicated, which renders support for the therapeutic effect of dupilumab in the treatment of AA. Scalp samples of patients with AA have demonstrated upregulation of T_H2, helper T-cell type 1 (T_H1), and IL-23 cytokines, suggesting efficacy with the use of anti-T_H2, anti-T_H1, and anti–IL-23 therapies.⁷ Polymerase chain reaction testing performed on serum samples in patients with AA displayed marked elevation of T_H2 cytokines, notably IL-13, which were reduced following intralesional corticosteroid treatment.⁸ It also has been demonstrated that multiple T_H2-related genes contribute to the genetic susceptibility of developing AA, specifically IL-4 and IL-13.^9,10

Prior case reports have shown contradicting effects (dupilumab-induced AA), which are speculated to be caused by a stronger T_H1 response from T_H2 suppression.^11,12 In one report, dupilumab was initiated for AD refractory to multiple topical and oral interventions. New-onset hair loss to the scalp was noted after 18 weeks of therapy. Twenty-six weeks into therapy with dupilumab, full hair regrowth was then reported.¹¹ Despite this report, our patient’s hair regrowth after the use of dupilumab for refractory AD further strengthens support for the use of dupilumab as a potential therapy for alopecia universalis and other lymphocyte-mediated hair loss conditions. However, a large disparity in response time and an overall slower progression of hair regrowth reported in our case separate it from other reports of rapid voluminous hair regrowth.^5,6 Our findings support the potential use of dupilumab in the treatment of patients with AA.

To the Editor:

The Moderna COVID-19 messenger RNA (mRNA) vaccine was authorized for use on December 18, 2020, with the second dose beginning on January 15, 2021.^1-3 Some individuals who received the Moderna vaccine experienced an intense rash known as “COVID arm,” a harmless but bothersome adverse effect that typically appears within a week and is a localized and transient immunogenic response.⁴ COVID arm differs from most vaccine adverse effects. The rash emerges not immediately but 5 to 9 days after the initial dose—on average, 1 week later. Apart from being itchy, the rash does not appear to be harmful and is not a reason to hesitate getting vaccinated.

Dermatologists and allergists have been studying this adverse effect, which has been formally termed delayed cutaneous hypersensitivity. Of potential clinical consequence is that the efficacy of the mRNA COVID-19 vaccine may be harmed if postvaccination dermal reactions necessitate systemic corticosteroid therapy. Because this vaccine stimulates an immune response as viral RNA integrates in cells secondary to production of the spike protein of the virus, the skin may be affected secondarily and manifestations of any underlying disease may be aggravated.⁵ We report a patient who developed a psoriasiform dermatitis after the first dose of the Moderna vaccine.

A 65-year-old woman presented to her primary care physician because of the severity of psoriasiform dermatitis that developed 5 days after she received the first dose of the Moderna COVID-19 mRNA vaccine. The patient had a medical history of Sjögren syndrome. Her medication history was negative, and her family history was negative for autoimmune disease. Physical examination by primary care revealed an erythematous scaly rash with plaques and papules on the neck and back (Figure 1). The patient presented again to primary care 2 days later with swollen, painful, discolored digits (Figure 2) and a stiff, sore neck.

Laboratory results were positive for anti–Sjögren syndrome–related antigens A and B. A complete blood cell count; comprehensive metabolic panel; erythrocyte sedimentation rate; and assays of rheumatoid factor, C-reactive protein, and anti–cyclic citrullinated peptide were within reference range. A biopsy of a lesion on the back showed psoriasiform dermatitis with confluent parakeratosis and scattered necrotic keratinocytes. There was superficial perivascular inflammation with rare eosinophils (Figure 3).

The patient was treated with a course of systemic corticosteroids. The rash resolved in 1 week. She did not receive the second dose due to the rash.

Two mRNA COVID-19 vaccines—Pfizer BioNTech and Moderna—have been granted emergency use authorization by the US Food and Drug Administration.⁶ The safety profile of the mRNA-1273 vaccine for the median 2-month follow-up showed no safety concerns.³ Minor localized adverse effects (eg, pain, redness, swelling) have been observed more frequently with the vaccines than with placebo. Systemic symptoms, such as fever, fatigue, headache, and muscle and joint pain, also were seen somewhat more often with the vaccines than with placebo; most such effects occurred 24 to 48 hours after vaccination.^3,6,7 The frequency of unsolicited adverse events and serious adverse events reported during the 28-day period after vaccination generally was similar among participants in the vaccine and placebo groups.³

There are 2 types of reactions to COVID-19 vaccination: immediate and delayed. Immediate reactions usually are due to anaphylaxis, requiring prompt recognition and treatment with epinephrine to stop rapid progression of life-threatening symptoms. Delayed reactions include localized reactions, such as urticaria and benign exanthema; serum sickness and serum sickness–like reactions; fever; and rare skin, organ, and neurologic sequelae.^1,6-8

Cutaneous manifestations, present in 16% to 50% of patients with Sjögren syndrome, are considered one of the most common extraglandular presentations of the syndrome. They are classified as nonvascular (eg, xerosis, angular cheilitis, eyelid dermatitis, annular erythema) and vascular (eg, Raynaud phenomenon, vasculitis).^9-11 Our patient did not have any of those findings. She had not taken any medications before the rash appeared, thereby ruling out a drug reaction.

The differential for our patient included post–urinary tract infection immune-reactive arthritis and rash, which is not typical with Escherichia coli infection but is described with infection with Chlamydia species and Salmonella species. Moreover, post–urinary tract infection immune-reactive arthritis and rash appear mostly on the palms and soles. Systemic lupus erythematosus–like rashes have a different histology and appear on sun-exposed areas; our patient’s rash was found mainly on unexposed areas.¹²

Because our patient received the Moderna vaccine 5 days before the rash appeared and later developed swelling of the digits with morning stiffness, a delayed serum sickness–like reaction secondary to COVID-19 vaccination was possible.^3,6

COVID-19 mRNA vaccines developed by Pfizer-BioNTech and Moderna incorporate a lipid-based nanoparticle carrier system that prevents rapid enzymatic degradation of mRNA and facilitates in vivo delivery of mRNA. This lipid-based nanoparticle carrier system is further stabilized by a polyethylene glycol 2000 lipid conjugate that provides a hydrophilic layer, thus prolonging half-life. The presence of lipid polyethylene glycol 2000 in mRNA vaccines has led to concern that this component could be implicated in anaphylaxis.⁶

COVID-19 antigens can give rise to varying clinical manifestations that are directly related to viral tissue damage or are indirectly induced by the antiviral immune response.^13,14 Hyperactivation of the immune system to eradicate COVID-19 may trigger autoimmunity; several immune-mediated disorders have been described in individuals infected with SARS-CoV-2. Dermal manifestations include cutaneous rash and vasculitis.^13-16 Crucial immunologic steps occur during SARS-CoV-2 infection that may link autoimmunity to COVID-19.^13,14 In preliminary published data on the efficacy of the Moderna vaccine on 45 trial enrollees, 3 did not receive the second dose of vaccination, including 1 who developed urticaria on both legs 5 days after the first dose.¹

Introduction of viral RNA can induce autoimmunity that can be explained by various phenomena, including epitope spreading, molecular mimicry, cryptic antigen, and bystander activation. Remarkably, more than one-third of immunogenic proteins in SARS-CoV-2 have potentially problematic homology to proteins that are key to the human adaptive immune system.⁵

Moreover, SARS-CoV-2 seems to induce organ injury through alternative mechanisms beyond direct viral infection, including immunologic injury. In some situations, hyperactivation of the immune response to SARS-CoV-2 RNA can result in autoimmune disease. COVID-19 has been associated with immune-mediated systemic or organ-selective manifestations, some of which fulfill the diagnostic or classification criteria of specific autoimmune diseases. It is unclear whether those medical disorders are the result of transitory postinfectious epiphenomena.⁵

A few studies have shown that patients with rheumatic disease have an incidence and prevalence of COVID-19 that is similar to the general population. A similar pattern has been detected in COVID-19 morbidity and mortality rates, even among patients with an autoimmune disease, such as rheumatoid arthritis and Sjögren syndrome.^5,17 Furthermore, exacerbation of preexisting rheumatic symptoms may be due to hyperactivation of antiviral pathways in a person with an autoimmune disease.^17-19 The findings in our patient suggested a direct role for the vaccine in skin manifestations, rather than for reactivation or development of new systemic autoimmune processes, such as systemic lupus erythematosus.

Exacerbation of psoriasis following COVID-19 vaccination has been described²⁰; however, the case patient did not have a history of psoriasis. The mechanism(s) of such exacerbation remain unclear; COVID-19 vaccine–induced helper T cells (T_H17) may play a role.²¹ Other skin manifestations encountered following COVID-19 vaccination include lichen planus, leukocytoclastic vasculitic rash, erythema multiforme–like rash, and pityriasis rosea–like rash.^22-25 The immune mechanisms of these manifestations remain unclear.

The clinical presentation of delayed vaccination reactions can be attributed to the timing of symptoms and, in this case, the immune-mediated background of a psoriasiform reaction. Although adverse reactions to the SARS-CoV-2 mRNA vaccine are rare, more individuals should be studied after vaccination to confirm and better understand this phenomenon.

To the Editor:

The Moderna COVID-19 messenger RNA (mRNA) vaccine was authorized for use on December 18, 2020, with the second dose beginning on January 15, 2021.^1-3 Some individuals who received the Moderna vaccine experienced an intense rash known as “COVID arm,” a harmless but bothersome adverse effect that typically appears within a week and is a localized and transient immunogenic response.⁴ COVID arm differs from most vaccine adverse effects. The rash emerges not immediately but 5 to 9 days after the initial dose—on average, 1 week later. Apart from being itchy, the rash does not appear to be harmful and is not a reason to hesitate getting vaccinated.

Dermatologists and allergists have been studying this adverse effect, which has been formally termed delayed cutaneous hypersensitivity. Of potential clinical consequence is that the efficacy of the mRNA COVID-19 vaccine may be harmed if postvaccination dermal reactions necessitate systemic corticosteroid therapy. Because this vaccine stimulates an immune response as viral RNA integrates in cells secondary to production of the spike protein of the virus, the skin may be affected secondarily and manifestations of any underlying disease may be aggravated.⁵ We report a patient who developed a psoriasiform dermatitis after the first dose of the Moderna vaccine.

A 65-year-old woman presented to her primary care physician because of the severity of psoriasiform dermatitis that developed 5 days after she received the first dose of the Moderna COVID-19 mRNA vaccine. The patient had a medical history of Sjögren syndrome. Her medication history was negative, and her family history was negative for autoimmune disease. Physical examination by primary care revealed an erythematous scaly rash with plaques and papules on the neck and back (Figure 1). The patient presented again to primary care 2 days later with swollen, painful, discolored digits (Figure 2) and a stiff, sore neck.

Laboratory results were positive for anti–Sjögren syndrome–related antigens A and B. A complete blood cell count; comprehensive metabolic panel; erythrocyte sedimentation rate; and assays of rheumatoid factor, C-reactive protein, and anti–cyclic citrullinated peptide were within reference range. A biopsy of a lesion on the back showed psoriasiform dermatitis with confluent parakeratosis and scattered necrotic keratinocytes. There was superficial perivascular inflammation with rare eosinophils (Figure 3).

The patient was treated with a course of systemic corticosteroids. The rash resolved in 1 week. She did not receive the second dose due to the rash.

Two mRNA COVID-19 vaccines—Pfizer BioNTech and Moderna—have been granted emergency use authorization by the US Food and Drug Administration.⁶ The safety profile of the mRNA-1273 vaccine for the median 2-month follow-up showed no safety concerns.³ Minor localized adverse effects (eg, pain, redness, swelling) have been observed more frequently with the vaccines than with placebo. Systemic symptoms, such as fever, fatigue, headache, and muscle and joint pain, also were seen somewhat more often with the vaccines than with placebo; most such effects occurred 24 to 48 hours after vaccination.^3,6,7 The frequency of unsolicited adverse events and serious adverse events reported during the 28-day period after vaccination generally was similar among participants in the vaccine and placebo groups.³

There are 2 types of reactions to COVID-19 vaccination: immediate and delayed. Immediate reactions usually are due to anaphylaxis, requiring prompt recognition and treatment with epinephrine to stop rapid progression of life-threatening symptoms. Delayed reactions include localized reactions, such as urticaria and benign exanthema; serum sickness and serum sickness–like reactions; fever; and rare skin, organ, and neurologic sequelae.^1,6-8

Cutaneous manifestations, present in 16% to 50% of patients with Sjögren syndrome, are considered one of the most common extraglandular presentations of the syndrome. They are classified as nonvascular (eg, xerosis, angular cheilitis, eyelid dermatitis, annular erythema) and vascular (eg, Raynaud phenomenon, vasculitis).^9-11 Our patient did not have any of those findings. She had not taken any medications before the rash appeared, thereby ruling out a drug reaction.

The differential for our patient included post–urinary tract infection immune-reactive arthritis and rash, which is not typical with Escherichia coli infection but is described with infection with Chlamydia species and Salmonella species. Moreover, post–urinary tract infection immune-reactive arthritis and rash appear mostly on the palms and soles. Systemic lupus erythematosus–like rashes have a different histology and appear on sun-exposed areas; our patient’s rash was found mainly on unexposed areas.¹²

Because our patient received the Moderna vaccine 5 days before the rash appeared and later developed swelling of the digits with morning stiffness, a delayed serum sickness–like reaction secondary to COVID-19 vaccination was possible.^3,6

COVID-19 mRNA vaccines developed by Pfizer-BioNTech and Moderna incorporate a lipid-based nanoparticle carrier system that prevents rapid enzymatic degradation of mRNA and facilitates in vivo delivery of mRNA. This lipid-based nanoparticle carrier system is further stabilized by a polyethylene glycol 2000 lipid conjugate that provides a hydrophilic layer, thus prolonging half-life. The presence of lipid polyethylene glycol 2000 in mRNA vaccines has led to concern that this component could be implicated in anaphylaxis.⁶

COVID-19 antigens can give rise to varying clinical manifestations that are directly related to viral tissue damage or are indirectly induced by the antiviral immune response.^13,14 Hyperactivation of the immune system to eradicate COVID-19 may trigger autoimmunity; several immune-mediated disorders have been described in individuals infected with SARS-CoV-2. Dermal manifestations include cutaneous rash and vasculitis.^13-16 Crucial immunologic steps occur during SARS-CoV-2 infection that may link autoimmunity to COVID-19.^13,14 In preliminary published data on the efficacy of the Moderna vaccine on 45 trial enrollees, 3 did not receive the second dose of vaccination, including 1 who developed urticaria on both legs 5 days after the first dose.¹

Introduction of viral RNA can induce autoimmunity that can be explained by various phenomena, including epitope spreading, molecular mimicry, cryptic antigen, and bystander activation. Remarkably, more than one-third of immunogenic proteins in SARS-CoV-2 have potentially problematic homology to proteins that are key to the human adaptive immune system.⁵

Moreover, SARS-CoV-2 seems to induce organ injury through alternative mechanisms beyond direct viral infection, including immunologic injury. In some situations, hyperactivation of the immune response to SARS-CoV-2 RNA can result in autoimmune disease. COVID-19 has been associated with immune-mediated systemic or organ-selective manifestations, some of which fulfill the diagnostic or classification criteria of specific autoimmune diseases. It is unclear whether those medical disorders are the result of transitory postinfectious epiphenomena.⁵

A few studies have shown that patients with rheumatic disease have an incidence and prevalence of COVID-19 that is similar to the general population. A similar pattern has been detected in COVID-19 morbidity and mortality rates, even among patients with an autoimmune disease, such as rheumatoid arthritis and Sjögren syndrome.^5,17 Furthermore, exacerbation of preexisting rheumatic symptoms may be due to hyperactivation of antiviral pathways in a person with an autoimmune disease.^17-19 The findings in our patient suggested a direct role for the vaccine in skin manifestations, rather than for reactivation or development of new systemic autoimmune processes, such as systemic lupus erythematosus.

Exacerbation of psoriasis following COVID-19 vaccination has been described²⁰; however, the case patient did not have a history of psoriasis. The mechanism(s) of such exacerbation remain unclear; COVID-19 vaccine–induced helper T cells (T_H17) may play a role.²¹ Other skin manifestations encountered following COVID-19 vaccination include lichen planus, leukocytoclastic vasculitic rash, erythema multiforme–like rash, and pityriasis rosea–like rash.^22-25 The immune mechanisms of these manifestations remain unclear.

The clinical presentation of delayed vaccination reactions can be attributed to the timing of symptoms and, in this case, the immune-mediated background of a psoriasiform reaction. Although adverse reactions to the SARS-CoV-2 mRNA vaccine are rare, more individuals should be studied after vaccination to confirm and better understand this phenomenon.

To the Editor:

The Moderna COVID-19 messenger RNA (mRNA) vaccine was authorized for use on December 18, 2020, with the second dose beginning on January 15, 2021.^1-3 Some individuals who received the Moderna vaccine experienced an intense rash known as “COVID arm,” a harmless but bothersome adverse effect that typically appears within a week and is a localized and transient immunogenic response.⁴ COVID arm differs from most vaccine adverse effects. The rash emerges not immediately but 5 to 9 days after the initial dose—on average, 1 week later. Apart from being itchy, the rash does not appear to be harmful and is not a reason to hesitate getting vaccinated.

Dermatologists and allergists have been studying this adverse effect, which has been formally termed delayed cutaneous hypersensitivity. Of potential clinical consequence is that the efficacy of the mRNA COVID-19 vaccine may be harmed if postvaccination dermal reactions necessitate systemic corticosteroid therapy. Because this vaccine stimulates an immune response as viral RNA integrates in cells secondary to production of the spike protein of the virus, the skin may be affected secondarily and manifestations of any underlying disease may be aggravated.⁵ We report a patient who developed a psoriasiform dermatitis after the first dose of the Moderna vaccine.

A 65-year-old woman presented to her primary care physician because of the severity of psoriasiform dermatitis that developed 5 days after she received the first dose of the Moderna COVID-19 mRNA vaccine. The patient had a medical history of Sjögren syndrome. Her medication history was negative, and her family history was negative for autoimmune disease. Physical examination by primary care revealed an erythematous scaly rash with plaques and papules on the neck and back (Figure 1). The patient presented again to primary care 2 days later with swollen, painful, discolored digits (Figure 2) and a stiff, sore neck.

Laboratory results were positive for anti–Sjögren syndrome–related antigens A and B. A complete blood cell count; comprehensive metabolic panel; erythrocyte sedimentation rate; and assays of rheumatoid factor, C-reactive protein, and anti–cyclic citrullinated peptide were within reference range. A biopsy of a lesion on the back showed psoriasiform dermatitis with confluent parakeratosis and scattered necrotic keratinocytes. There was superficial perivascular inflammation with rare eosinophils (Figure 3).

The patient was treated with a course of systemic corticosteroids. The rash resolved in 1 week. She did not receive the second dose due to the rash.

Two mRNA COVID-19 vaccines—Pfizer BioNTech and Moderna—have been granted emergency use authorization by the US Food and Drug Administration.⁶ The safety profile of the mRNA-1273 vaccine for the median 2-month follow-up showed no safety concerns.³ Minor localized adverse effects (eg, pain, redness, swelling) have been observed more frequently with the vaccines than with placebo. Systemic symptoms, such as fever, fatigue, headache, and muscle and joint pain, also were seen somewhat more often with the vaccines than with placebo; most such effects occurred 24 to 48 hours after vaccination.^3,6,7 The frequency of unsolicited adverse events and serious adverse events reported during the 28-day period after vaccination generally was similar among participants in the vaccine and placebo groups.³

There are 2 types of reactions to COVID-19 vaccination: immediate and delayed. Immediate reactions usually are due to anaphylaxis, requiring prompt recognition and treatment with epinephrine to stop rapid progression of life-threatening symptoms. Delayed reactions include localized reactions, such as urticaria and benign exanthema; serum sickness and serum sickness–like reactions; fever; and rare skin, organ, and neurologic sequelae.^1,6-8

Cutaneous manifestations, present in 16% to 50% of patients with Sjögren syndrome, are considered one of the most common extraglandular presentations of the syndrome. They are classified as nonvascular (eg, xerosis, angular cheilitis, eyelid dermatitis, annular erythema) and vascular (eg, Raynaud phenomenon, vasculitis).^9-11 Our patient did not have any of those findings. She had not taken any medications before the rash appeared, thereby ruling out a drug reaction.

The differential for our patient included post–urinary tract infection immune-reactive arthritis and rash, which is not typical with Escherichia coli infection but is described with infection with Chlamydia species and Salmonella species. Moreover, post–urinary tract infection immune-reactive arthritis and rash appear mostly on the palms and soles. Systemic lupus erythematosus–like rashes have a different histology and appear on sun-exposed areas; our patient’s rash was found mainly on unexposed areas.¹²

Because our patient received the Moderna vaccine 5 days before the rash appeared and later developed swelling of the digits with morning stiffness, a delayed serum sickness–like reaction secondary to COVID-19 vaccination was possible.^3,6

COVID-19 mRNA vaccines developed by Pfizer-BioNTech and Moderna incorporate a lipid-based nanoparticle carrier system that prevents rapid enzymatic degradation of mRNA and facilitates in vivo delivery of mRNA. This lipid-based nanoparticle carrier system is further stabilized by a polyethylene glycol 2000 lipid conjugate that provides a hydrophilic layer, thus prolonging half-life. The presence of lipid polyethylene glycol 2000 in mRNA vaccines has led to concern that this component could be implicated in anaphylaxis.⁶

COVID-19 antigens can give rise to varying clinical manifestations that are directly related to viral tissue damage or are indirectly induced by the antiviral immune response.^13,14 Hyperactivation of the immune system to eradicate COVID-19 may trigger autoimmunity; several immune-mediated disorders have been described in individuals infected with SARS-CoV-2. Dermal manifestations include cutaneous rash and vasculitis.^13-16 Crucial immunologic steps occur during SARS-CoV-2 infection that may link autoimmunity to COVID-19.^13,14 In preliminary published data on the efficacy of the Moderna vaccine on 45 trial enrollees, 3 did not receive the second dose of vaccination, including 1 who developed urticaria on both legs 5 days after the first dose.¹

Introduction of viral RNA can induce autoimmunity that can be explained by various phenomena, including epitope spreading, molecular mimicry, cryptic antigen, and bystander activation. Remarkably, more than one-third of immunogenic proteins in SARS-CoV-2 have potentially problematic homology to proteins that are key to the human adaptive immune system.⁵

Moreover, SARS-CoV-2 seems to induce organ injury through alternative mechanisms beyond direct viral infection, including immunologic injury. In some situations, hyperactivation of the immune response to SARS-CoV-2 RNA can result in autoimmune disease. COVID-19 has been associated with immune-mediated systemic or organ-selective manifestations, some of which fulfill the diagnostic or classification criteria of specific autoimmune diseases. It is unclear whether those medical disorders are the result of transitory postinfectious epiphenomena.⁵

A few studies have shown that patients with rheumatic disease have an incidence and prevalence of COVID-19 that is similar to the general population. A similar pattern has been detected in COVID-19 morbidity and mortality rates, even among patients with an autoimmune disease, such as rheumatoid arthritis and Sjögren syndrome.^5,17 Furthermore, exacerbation of preexisting rheumatic symptoms may be due to hyperactivation of antiviral pathways in a person with an autoimmune disease.^17-19 The findings in our patient suggested a direct role for the vaccine in skin manifestations, rather than for reactivation or development of new systemic autoimmune processes, such as systemic lupus erythematosus.

Exacerbation of psoriasis following COVID-19 vaccination has been described²⁰; however, the case patient did not have a history of psoriasis. The mechanism(s) of such exacerbation remain unclear; COVID-19 vaccine–induced helper T cells (T_H17) may play a role.²¹ Other skin manifestations encountered following COVID-19 vaccination include lichen planus, leukocytoclastic vasculitic rash, erythema multiforme–like rash, and pityriasis rosea–like rash.^22-25 The immune mechanisms of these manifestations remain unclear.

The clinical presentation of delayed vaccination reactions can be attributed to the timing of symptoms and, in this case, the immune-mediated background of a psoriasiform reaction. Although adverse reactions to the SARS-CoV-2 mRNA vaccine are rare, more individuals should be studied after vaccination to confirm and better understand this phenomenon.

The Diagnosis: Tuberous Xanthoma

The skin biopsy revealed a nodular collection of foam cells (quiz image [bottom]). Tuberous xanthoma was the most likely diagnosis based on the patient’s history as well as the clinical and histologic findings. Tuberous xanthomas are flat or elevated nodules in the dermis and subcutaneous tissue, commonly occurring on the skin over the joints.¹ Smaller nodules and papules often are referred to as tuberoeruptive xanthomas and exist on a continuum with the larger tuberous xanthomas. All xanthomas appear histologically similar, with collections of foam cells present within the dermis.² Foam cells form when serum lipoproteins diffuse through capillary walls, deposit in the skin or tendons, and are scavenged by monocytes.3 Tuberous xanthomas, along with tendinous, eruptive, and planar xanthomas, are the most likely to be associated with hyperlipidemia.⁴ They may indicate an underlying disorder of lipid metabolism, such as familial hypercholesterolemia.^1,3 This is the most common cause of inheritable cardiovascular disease, with a prevalence of approximately 1:250.² Premature cardiovascular disease risk increases 2 to 4 times in patients with familial hypercholesterolemia and tendinous xanthomas,¹ illustrating that recognition of cutaneous lesions can lead to earlier diagnosis and prevention of patient morbidity and mortality.

Juvenile xanthogranuloma typically presents as smooth yellow papules or nodules on the head and neck, with a characteristic “setting-sun” appearance (ie, yellow center with an erythematous halo) on dermoscopy.⁵ Histologically, juvenile xanthogranulomas are composed of foam cells and a mixed lymphohistiocytic infiltrate with eosinophils within the dermis. Giant cells with a ring of nuclei surrounded by cytoplasm containing lipid vacuoles (called Touton giant cells) are characteristic (Figure 1). In contrast to tuberous xanthomas, juvenile xanthogranulomas often present within the first year of life.⁶

Keloid scars are more prevalent in patients with skin of color. They are characterized by eosinophilic keloidal collagen with a whorled proliferation of fibroblasts on histology (Figure 2).⁷ They occur spontaneously or at sites of injury and present as bluish-red or flesh-colored firm papules or nodules.⁸ In our patient, keloid scars were an unlikely diagnosis due to the lack of trauma and the absence of keloidal collagen on histology.

Necrobiosis lipoidica diabeticorum typically presents as an erythematous, yellow-brown, circular plaque on the anterior lower leg in patients with diabetes mellitus; it rarely occurs in children.⁹ Microscopy shows palisaded granulomas surrounding necrobiotic collagen arranged horizontally in a layer cake–like fashion (Figure 3).^9,10 The etiology of necrobiosis lipoidica diabeticorum currently is unknown, though immune complex deposition may contribute to its pathology. It has been associated with type 1 diabetes mellitus, though severity of the lesions is not associated with extent of glycemic control.¹⁰

Rosai-Dorfman disease is an uncommon disorder characterized by a proliferation of histiocytes that most often presents as bilateral cervical lymphadenopathy in children and young adults but rarely can present with cutaneous lesions when extranodal involvement is present.^11,12 The cutaneous form most commonly presents as red papules or nodules. On histology, the lesions exhibit a nodular dermal proliferation of histiocytes and smaller lymphocytoid cells with a marbled or starry sky–like appearance on low power (Figure 4). On higher magnification, the characteristic finding of emperipolesis can be seen.11 On immunohistochemistry, the histiocytes stain positively for CD68 and S-100. Although the pathogenesis currently is unknown, evidence of clonality indicates the disease may be related to a neoplastic process.¹²

The Diagnosis: Tuberous Xanthoma

The skin biopsy revealed a nodular collection of foam cells (quiz image [bottom]). Tuberous xanthoma was the most likely diagnosis based on the patient’s history as well as the clinical and histologic findings. Tuberous xanthomas are flat or elevated nodules in the dermis and subcutaneous tissue, commonly occurring on the skin over the joints.¹ Smaller nodules and papules often are referred to as tuberoeruptive xanthomas and exist on a continuum with the larger tuberous xanthomas. All xanthomas appear histologically similar, with collections of foam cells present within the dermis.² Foam cells form when serum lipoproteins diffuse through capillary walls, deposit in the skin or tendons, and are scavenged by monocytes.3 Tuberous xanthomas, along with tendinous, eruptive, and planar xanthomas, are the most likely to be associated with hyperlipidemia.⁴ They may indicate an underlying disorder of lipid metabolism, such as familial hypercholesterolemia.^1,3 This is the most common cause of inheritable cardiovascular disease, with a prevalence of approximately 1:250.² Premature cardiovascular disease risk increases 2 to 4 times in patients with familial hypercholesterolemia and tendinous xanthomas,¹ illustrating that recognition of cutaneous lesions can lead to earlier diagnosis and prevention of patient morbidity and mortality.

Juvenile xanthogranuloma typically presents as smooth yellow papules or nodules on the head and neck, with a characteristic “setting-sun” appearance (ie, yellow center with an erythematous halo) on dermoscopy.⁵ Histologically, juvenile xanthogranulomas are composed of foam cells and a mixed lymphohistiocytic infiltrate with eosinophils within the dermis. Giant cells with a ring of nuclei surrounded by cytoplasm containing lipid vacuoles (called Touton giant cells) are characteristic (Figure 1). In contrast to tuberous xanthomas, juvenile xanthogranulomas often present within the first year of life.⁶

Keloid scars are more prevalent in patients with skin of color. They are characterized by eosinophilic keloidal collagen with a whorled proliferation of fibroblasts on histology (Figure 2).⁷ They occur spontaneously or at sites of injury and present as bluish-red or flesh-colored firm papules or nodules.⁸ In our patient, keloid scars were an unlikely diagnosis due to the lack of trauma and the absence of keloidal collagen on histology.

Necrobiosis lipoidica diabeticorum typically presents as an erythematous, yellow-brown, circular plaque on the anterior lower leg in patients with diabetes mellitus; it rarely occurs in children.⁹ Microscopy shows palisaded granulomas surrounding necrobiotic collagen arranged horizontally in a layer cake–like fashion (Figure 3).^9,10 The etiology of necrobiosis lipoidica diabeticorum currently is unknown, though immune complex deposition may contribute to its pathology. It has been associated with type 1 diabetes mellitus, though severity of the lesions is not associated with extent of glycemic control.¹⁰

Rosai-Dorfman disease is an uncommon disorder characterized by a proliferation of histiocytes that most often presents as bilateral cervical lymphadenopathy in children and young adults but rarely can present with cutaneous lesions when extranodal involvement is present.^11,12 The cutaneous form most commonly presents as red papules or nodules. On histology, the lesions exhibit a nodular dermal proliferation of histiocytes and smaller lymphocytoid cells with a marbled or starry sky–like appearance on low power (Figure 4). On higher magnification, the characteristic finding of emperipolesis can be seen.11 On immunohistochemistry, the histiocytes stain positively for CD68 and S-100. Although the pathogenesis currently is unknown, evidence of clonality indicates the disease may be related to a neoplastic process.¹²

The Diagnosis: Tuberous Xanthoma

The skin biopsy revealed a nodular collection of foam cells (quiz image [bottom]). Tuberous xanthoma was the most likely diagnosis based on the patient’s history as well as the clinical and histologic findings. Tuberous xanthomas are flat or elevated nodules in the dermis and subcutaneous tissue, commonly occurring on the skin over the joints.¹ Smaller nodules and papules often are referred to as tuberoeruptive xanthomas and exist on a continuum with the larger tuberous xanthomas. All xanthomas appear histologically similar, with collections of foam cells present within the dermis.² Foam cells form when serum lipoproteins diffuse through capillary walls, deposit in the skin or tendons, and are scavenged by monocytes.3 Tuberous xanthomas, along with tendinous, eruptive, and planar xanthomas, are the most likely to be associated with hyperlipidemia.⁴ They may indicate an underlying disorder of lipid metabolism, such as familial hypercholesterolemia.^1,3 This is the most common cause of inheritable cardiovascular disease, with a prevalence of approximately 1:250.² Premature cardiovascular disease risk increases 2 to 4 times in patients with familial hypercholesterolemia and tendinous xanthomas,¹ illustrating that recognition of cutaneous lesions can lead to earlier diagnosis and prevention of patient morbidity and mortality.

Juvenile xanthogranuloma typically presents as smooth yellow papules or nodules on the head and neck, with a characteristic “setting-sun” appearance (ie, yellow center with an erythematous halo) on dermoscopy.⁵ Histologically, juvenile xanthogranulomas are composed of foam cells and a mixed lymphohistiocytic infiltrate with eosinophils within the dermis. Giant cells with a ring of nuclei surrounded by cytoplasm containing lipid vacuoles (called Touton giant cells) are characteristic (Figure 1). In contrast to tuberous xanthomas, juvenile xanthogranulomas often present within the first year of life.⁶

Keloid scars are more prevalent in patients with skin of color. They are characterized by eosinophilic keloidal collagen with a whorled proliferation of fibroblasts on histology (Figure 2).⁷ They occur spontaneously or at sites of injury and present as bluish-red or flesh-colored firm papules or nodules.⁸ In our patient, keloid scars were an unlikely diagnosis due to the lack of trauma and the absence of keloidal collagen on histology.

Necrobiosis lipoidica diabeticorum typically presents as an erythematous, yellow-brown, circular plaque on the anterior lower leg in patients with diabetes mellitus; it rarely occurs in children.⁹ Microscopy shows palisaded granulomas surrounding necrobiotic collagen arranged horizontally in a layer cake–like fashion (Figure 3).^9,10 The etiology of necrobiosis lipoidica diabeticorum currently is unknown, though immune complex deposition may contribute to its pathology. It has been associated with type 1 diabetes mellitus, though severity of the lesions is not associated with extent of glycemic control.¹⁰

Rosai-Dorfman disease is an uncommon disorder characterized by a proliferation of histiocytes that most often presents as bilateral cervical lymphadenopathy in children and young adults but rarely can present with cutaneous lesions when extranodal involvement is present.^11,12 The cutaneous form most commonly presents as red papules or nodules. On histology, the lesions exhibit a nodular dermal proliferation of histiocytes and smaller lymphocytoid cells with a marbled or starry sky–like appearance on low power (Figure 4). On higher magnification, the characteristic finding of emperipolesis can be seen.11 On immunohistochemistry, the histiocytes stain positively for CD68 and S-100. Although the pathogenesis currently is unknown, evidence of clonality indicates the disease may be related to a neoplastic process.¹²

Reactions to poison ivy, poison oak, and poison sumac, which affect 10 to 50 million Americans a year,¹ are classified as Toxicodendron dermatitis; 50% to 75% of US adults are clinically sensitive to these plants.² Furthermore, people of all ethnicities, skin types, and ages residing in most US geographical regions are at risk.³ Allergenicity is caused by urushiol, which is found in members of the Anacardiaceae family.⁴ Once absorbed, urushiol causes a type IV hypersensitivity reaction in those who are susceptible.⁵

Cutaneous Manifestations

Toxicodendron dermatitis presents with an acute eczematous eruption characterized by streaks of intensely pruritic and erythematous papules and vesicles (Figure 1). Areas of involvement are characterized by sharp margins that follow the pattern of contact made by the plant’s leaves, berries, stems, and vines.⁶ The fluid content of the vesicles is not antigenic and cannot cause subsequent transmission to oneself or others.³ A person with prior contact to the plant who becomes sensitized develops an eruption 24 to 48 hours after subsequent contact with the plant; peak severity manifests 1 to 14 days later.⁷

When left untreated, the eruption can last 3 weeks. If the plant is burned, urushiol can be aerosolized in smoke, causing respiratory tract inflammation and generalized dermatitis, which has been reported among wildland firefighters.² Long-term complications from an outbreak are limited but can include postinflammatory hyperpigmentation and secondary bacterial infection.⁸ Rare reports of nephrotic syndrome also have appeared in the literature.⁹Toxicodendron dermatitis can present distinctively as so-called black dot dermatitis.⁶

Nomenclature

Poison ivy, poison oak, and poison sumac are members of the family Anacardiaceae and genus Toxicodendron,⁶ derived from the Greek words toxikos (poison) and dendron (tree).¹⁰

Distribution

Toxicodendron plants characteristically are found in various regions of the United States. Poison ivy is the most common and is comprised of 2 species: Toxicodendron rydbergii and Toxicodendron radicans. Toxicodendron rydbergii is a nonclimbing dwarf shrub typically found in the northern and western United States. Toxicodendron radicans is a climbing vine found in the eastern United States. Poison oak also is comprised of 2 species—Toxicodendron toxicarium and Toxicodendron diversilobum—and is more common in the western United States. Poison sumac (also known as Toxicodendron vernix) is a small shrub that grows in moist swampy areas. It has a predilection for marshes of the eastern and southeastern United States.^6,11

Identifying Features

Educating patients on how to identify poison ivy can play a key role in avoidance, which is the most important step in preventing Toxicodendron dermatitis. A challenge in identification of poison ivy is the plant’s variable appearance; it grows as a small shrub, low-lying vine, or vine that climbs other trees.

As the vine matures, it develops tiny, rough, “hairy” rootlets—hence the saying, “Hairy vine, no friend of mine!” Rootlets help the plant attach to trees growing near a water source. Vines can reach a diameter of 3 inches. From mature vines, solitary stems extend 1 to 2 inches with 3 characteristic leaves at the terminus (Figure 2), prompting another classic saying, “Leaves of 3, let it be!”¹²

Poison oak is characterized by 3 to 5 leaflets. Poison sumac has 7 to 13 pointed, smooth-edged leaves.⁶

Dermatitis-Inducing Plant Parts

The primary allergenic component of Toxicodendron plants is urushiol, a resinous sap found in stems, roots, leaves, and skins of the fruits. These components must be damaged or bruised to release the allergen; slight contact with an uninjured plant part might not lead to harm.^2,13 Some common forms of transmission include skin contact, ingestion, inhalation of smoke from burning plants, and contact with skin through contaminated items, such as clothing, animals, and tools.¹⁴

Allergens

The catecholic ring and aliphatic chain of the urushiol molecule are allergenic.¹⁵ The degree of saturation and length of the side chains vary with different catechols. Urushiol displays cross-reactivity with poison ivy, poison oak, and poison sumac. Urushiol from these plants differs only slightly in structure; therefore, sensitization to one causes sensitization to all. There also is cross-reactivity between different members of the Anacardiaceae family, including Anacardium occidentale (tropical cashew nut), Mangifera indica (tropical mango tree), Ginkgo biloba (ginkgo tree), and Semecarpus anacardium (Indian marking nut tree).¹²

Poison ivy, poison oak, and poison sumac cause allergic contact dermatitis as a type IV hypersensitivity reaction. First, urushiol binds and penetrates the skin, where it is oxidized to quinone intermediates and bound to haptens. Then, the intermediates bind surface proteins on antigen-presenting cells, specifically Langerhans cells in the epidermis and dermis.⁵

Presentation of nonpeptide antigens, such as urushiol, to T cells requires expression of langerin (also known as CD207) and CD1a.¹⁶ Langerin is a C-type lectin that causes formation of Birbeck granules; CD1a is a major histocompatibility complex class I molecule found in Birbeck granules.^5,17 After Langerhans cells internalize and process the urushiol self-hapten neoantigen, it is presented to CD4⁺ T cells.⁶ These cells then expand to form circulating activated T-effector and T-memory lymphocytes.¹⁸

The molecular link that occurs between the hapten and carrier protein determines the response. When linked by an amino nucleophile, selective induction of T-effector cells ensues, resulting in allergic contact dermatitis. When linked by a sulfhydryl bond, selective induction of suppressor cells occurs, resulting in a reduced allergic contact dermatitis response.¹⁹ In the case of activation of T-effector cells, a cell-mediated cytotoxic immune response is generated that destroys epidermal cells and dermal vasculature.² The incidence and intensity of poison ivy sensitivity decline proportionally with age and the absence of continued exposure.²⁰

Preventive Action—Patients should be counseled that if contact between plant and skin occurs, it is important to remove contaminated clothing or objects and wash them with soap to prevent additional exposure.^14,21 Areas of the skin that made contact with the plant should be washed with water as soon as possible; after 30 minutes, urushiol has sufficiently penetrated to cause a reaction.² Forceful unidirectional washing with a damp washcloth and liquid dishwashing soap is recommended.²²

Several barrier creams are commercially available to help prevent absorption or to deactivate the urushiol antigen. These products are used widely by forestry workers and wildland firefighters.²³ One such barrier cream is bentoquatam (sold as various trade names), an organoclay compound made of quaternium-18 bentonite that interferes with absorption of the allergen by acting as a physical blocker.²⁴

Treatment

After Toxicodendron dermatitis develops, several treatments are available to help manage symptoms. Calamine lotion can be used to help dry weeping lesions.^25,26 Topical steroids can be used to help control pruritus and alleviate inflammation. High-potency topical corticosteroids such as clobetasol and mid-potency steroids such as triamcinolone can be used. Topical anesthetics (eg, benzocaine, pramoxine, benzyl alcohol) might provide symptomatic relief.^27,28

Oral antihistamines can allow for better sleep by providing sedation but do not target the pruritus of poison ivy dermatitis, which is not histamine mediated.^29,30 Systemic corticosteroids usually are considered in more severe dermatitis—when 20% or more of the body surface area is involved; blistering and itching are severe; or the face, hands, or genitalia are involved.^31,32

Clinical Uses

Therapeutic uses for poison ivy have been explored extensively. In 1892, Dakin³³ reported that ingestion of leaves by Native Americans reduced the incidence and severity of skin lesions after contact with poison ivy. Consumption of poison ivy was further studied by Epstein and colleagues³⁴ in 1974; they concluded that ingestion of a large amount of urushiol over a period of 3 months or longer may help with hyposensitization—but not complete desensitization—to contact with poison ivy. However, the risk for adverse effects is thought to outweigh benefits because ingestion can cause perianal dermatitis, mucocutaneous sequelae, and systemic contact dermatitis.²

Although the use of Toxicodendron plants in modern-day medicine is limited, development of a vaccine (immunotherapy) against Toxicodendron dermatitis offers an exciting opportunity for further research.

Reactions to poison ivy, poison oak, and poison sumac, which affect 10 to 50 million Americans a year,¹ are classified as Toxicodendron dermatitis; 50% to 75% of US adults are clinically sensitive to these plants.² Furthermore, people of all ethnicities, skin types, and ages residing in most US geographical regions are at risk.³ Allergenicity is caused by urushiol, which is found in members of the Anacardiaceae family.⁴ Once absorbed, urushiol causes a type IV hypersensitivity reaction in those who are susceptible.⁵

Cutaneous Manifestations

Toxicodendron dermatitis presents with an acute eczematous eruption characterized by streaks of intensely pruritic and erythematous papules and vesicles (Figure 1). Areas of involvement are characterized by sharp margins that follow the pattern of contact made by the plant’s leaves, berries, stems, and vines.⁶ The fluid content of the vesicles is not antigenic and cannot cause subsequent transmission to oneself or others.³ A person with prior contact to the plant who becomes sensitized develops an eruption 24 to 48 hours after subsequent contact with the plant; peak severity manifests 1 to 14 days later.⁷

When left untreated, the eruption can last 3 weeks. If the plant is burned, urushiol can be aerosolized in smoke, causing respiratory tract inflammation and generalized dermatitis, which has been reported among wildland firefighters.² Long-term complications from an outbreak are limited but can include postinflammatory hyperpigmentation and secondary bacterial infection.⁸ Rare reports of nephrotic syndrome also have appeared in the literature.⁹Toxicodendron dermatitis can present distinctively as so-called black dot dermatitis.⁶

Nomenclature

Poison ivy, poison oak, and poison sumac are members of the family Anacardiaceae and genus Toxicodendron,⁶ derived from the Greek words toxikos (poison) and dendron (tree).¹⁰

Distribution

Toxicodendron plants characteristically are found in various regions of the United States. Poison ivy is the most common and is comprised of 2 species: Toxicodendron rydbergii and Toxicodendron radicans. Toxicodendron rydbergii is a nonclimbing dwarf shrub typically found in the northern and western United States. Toxicodendron radicans is a climbing vine found in the eastern United States. Poison oak also is comprised of 2 species—Toxicodendron toxicarium and Toxicodendron diversilobum—and is more common in the western United States. Poison sumac (also known as Toxicodendron vernix) is a small shrub that grows in moist swampy areas. It has a predilection for marshes of the eastern and southeastern United States.^6,11

Identifying Features

Educating patients on how to identify poison ivy can play a key role in avoidance, which is the most important step in preventing Toxicodendron dermatitis. A challenge in identification of poison ivy is the plant’s variable appearance; it grows as a small shrub, low-lying vine, or vine that climbs other trees.

As the vine matures, it develops tiny, rough, “hairy” rootlets—hence the saying, “Hairy vine, no friend of mine!” Rootlets help the plant attach to trees growing near a water source. Vines can reach a diameter of 3 inches. From mature vines, solitary stems extend 1 to 2 inches with 3 characteristic leaves at the terminus (Figure 2), prompting another classic saying, “Leaves of 3, let it be!”¹²

Poison oak is characterized by 3 to 5 leaflets. Poison sumac has 7 to 13 pointed, smooth-edged leaves.⁶

Dermatitis-Inducing Plant Parts

The primary allergenic component of Toxicodendron plants is urushiol, a resinous sap found in stems, roots, leaves, and skins of the fruits. These components must be damaged or bruised to release the allergen; slight contact with an uninjured plant part might not lead to harm.^2,13 Some common forms of transmission include skin contact, ingestion, inhalation of smoke from burning plants, and contact with skin through contaminated items, such as clothing, animals, and tools.¹⁴

Allergens

The catecholic ring and aliphatic chain of the urushiol molecule are allergenic.¹⁵ The degree of saturation and length of the side chains vary with different catechols. Urushiol displays cross-reactivity with poison ivy, poison oak, and poison sumac. Urushiol from these plants differs only slightly in structure; therefore, sensitization to one causes sensitization to all. There also is cross-reactivity between different members of the Anacardiaceae family, including Anacardium occidentale (tropical cashew nut), Mangifera indica (tropical mango tree), Ginkgo biloba (ginkgo tree), and Semecarpus anacardium (Indian marking nut tree).¹²

Poison ivy, poison oak, and poison sumac cause allergic contact dermatitis as a type IV hypersensitivity reaction. First, urushiol binds and penetrates the skin, where it is oxidized to quinone intermediates and bound to haptens. Then, the intermediates bind surface proteins on antigen-presenting cells, specifically Langerhans cells in the epidermis and dermis.⁵

Presentation of nonpeptide antigens, such as urushiol, to T cells requires expression of langerin (also known as CD207) and CD1a.¹⁶ Langerin is a C-type lectin that causes formation of Birbeck granules; CD1a is a major histocompatibility complex class I molecule found in Birbeck granules.^5,17 After Langerhans cells internalize and process the urushiol self-hapten neoantigen, it is presented to CD4⁺ T cells.⁶ These cells then expand to form circulating activated T-effector and T-memory lymphocytes.¹⁸

The molecular link that occurs between the hapten and carrier protein determines the response. When linked by an amino nucleophile, selective induction of T-effector cells ensues, resulting in allergic contact dermatitis. When linked by a sulfhydryl bond, selective induction of suppressor cells occurs, resulting in a reduced allergic contact dermatitis response.¹⁹ In the case of activation of T-effector cells, a cell-mediated cytotoxic immune response is generated that destroys epidermal cells and dermal vasculature.² The incidence and intensity of poison ivy sensitivity decline proportionally with age and the absence of continued exposure.²⁰

Preventive Action—Patients should be counseled that if contact between plant and skin occurs, it is important to remove contaminated clothing or objects and wash them with soap to prevent additional exposure.^14,21 Areas of the skin that made contact with the plant should be washed with water as soon as possible; after 30 minutes, urushiol has sufficiently penetrated to cause a reaction.² Forceful unidirectional washing with a damp washcloth and liquid dishwashing soap is recommended.²²

Several barrier creams are commercially available to help prevent absorption or to deactivate the urushiol antigen. These products are used widely by forestry workers and wildland firefighters.²³ One such barrier cream is bentoquatam (sold as various trade names), an organoclay compound made of quaternium-18 bentonite that interferes with absorption of the allergen by acting as a physical blocker.²⁴

Treatment

After Toxicodendron dermatitis develops, several treatments are available to help manage symptoms. Calamine lotion can be used to help dry weeping lesions.^25,26 Topical steroids can be used to help control pruritus and alleviate inflammation. High-potency topical corticosteroids such as clobetasol and mid-potency steroids such as triamcinolone can be used. Topical anesthetics (eg, benzocaine, pramoxine, benzyl alcohol) might provide symptomatic relief.^27,28

Oral antihistamines can allow for better sleep by providing sedation but do not target the pruritus of poison ivy dermatitis, which is not histamine mediated.^29,30 Systemic corticosteroids usually are considered in more severe dermatitis—when 20% or more of the body surface area is involved; blistering and itching are severe; or the face, hands, or genitalia are involved.^31,32

Clinical Uses

Therapeutic uses for poison ivy have been explored extensively. In 1892, Dakin³³ reported that ingestion of leaves by Native Americans reduced the incidence and severity of skin lesions after contact with poison ivy. Consumption of poison ivy was further studied by Epstein and colleagues³⁴ in 1974; they concluded that ingestion of a large amount of urushiol over a period of 3 months or longer may help with hyposensitization—but not complete desensitization—to contact with poison ivy. However, the risk for adverse effects is thought to outweigh benefits because ingestion can cause perianal dermatitis, mucocutaneous sequelae, and systemic contact dermatitis.²

Although the use of Toxicodendron plants in modern-day medicine is limited, development of a vaccine (immunotherapy) against Toxicodendron dermatitis offers an exciting opportunity for further research.

Reactions to poison ivy, poison oak, and poison sumac, which affect 10 to 50 million Americans a year,¹ are classified as Toxicodendron dermatitis; 50% to 75% of US adults are clinically sensitive to these plants.² Furthermore, people of all ethnicities, skin types, and ages residing in most US geographical regions are at risk.³ Allergenicity is caused by urushiol, which is found in members of the Anacardiaceae family.⁴ Once absorbed, urushiol causes a type IV hypersensitivity reaction in those who are susceptible.⁵

Cutaneous Manifestations

Toxicodendron dermatitis presents with an acute eczematous eruption characterized by streaks of intensely pruritic and erythematous papules and vesicles (Figure 1). Areas of involvement are characterized by sharp margins that follow the pattern of contact made by the plant’s leaves, berries, stems, and vines.⁶ The fluid content of the vesicles is not antigenic and cannot cause subsequent transmission to oneself or others.³ A person with prior contact to the plant who becomes sensitized develops an eruption 24 to 48 hours after subsequent contact with the plant; peak severity manifests 1 to 14 days later.⁷

When left untreated, the eruption can last 3 weeks. If the plant is burned, urushiol can be aerosolized in smoke, causing respiratory tract inflammation and generalized dermatitis, which has been reported among wildland firefighters.² Long-term complications from an outbreak are limited but can include postinflammatory hyperpigmentation and secondary bacterial infection.⁸ Rare reports of nephrotic syndrome also have appeared in the literature.⁹Toxicodendron dermatitis can present distinctively as so-called black dot dermatitis.⁶

Nomenclature

Poison ivy, poison oak, and poison sumac are members of the family Anacardiaceae and genus Toxicodendron,⁶ derived from the Greek words toxikos (poison) and dendron (tree).¹⁰

Distribution

Toxicodendron plants characteristically are found in various regions of the United States. Poison ivy is the most common and is comprised of 2 species: Toxicodendron rydbergii and Toxicodendron radicans. Toxicodendron rydbergii is a nonclimbing dwarf shrub typically found in the northern and western United States. Toxicodendron radicans is a climbing vine found in the eastern United States. Poison oak also is comprised of 2 species—Toxicodendron toxicarium and Toxicodendron diversilobum—and is more common in the western United States. Poison sumac (also known as Toxicodendron vernix) is a small shrub that grows in moist swampy areas. It has a predilection for marshes of the eastern and southeastern United States.^6,11

Identifying Features

Educating patients on how to identify poison ivy can play a key role in avoidance, which is the most important step in preventing Toxicodendron dermatitis. A challenge in identification of poison ivy is the plant’s variable appearance; it grows as a small shrub, low-lying vine, or vine that climbs other trees.

As the vine matures, it develops tiny, rough, “hairy” rootlets—hence the saying, “Hairy vine, no friend of mine!” Rootlets help the plant attach to trees growing near a water source. Vines can reach a diameter of 3 inches. From mature vines, solitary stems extend 1 to 2 inches with 3 characteristic leaves at the terminus (Figure 2), prompting another classic saying, “Leaves of 3, let it be!”¹²

Poison oak is characterized by 3 to 5 leaflets. Poison sumac has 7 to 13 pointed, smooth-edged leaves.⁶

Dermatitis-Inducing Plant Parts

The primary allergenic component of Toxicodendron plants is urushiol, a resinous sap found in stems, roots, leaves, and skins of the fruits. These components must be damaged or bruised to release the allergen; slight contact with an uninjured plant part might not lead to harm.^2,13 Some common forms of transmission include skin contact, ingestion, inhalation of smoke from burning plants, and contact with skin through contaminated items, such as clothing, animals, and tools.¹⁴

Allergens

The catecholic ring and aliphatic chain of the urushiol molecule are allergenic.¹⁵ The degree of saturation and length of the side chains vary with different catechols. Urushiol displays cross-reactivity with poison ivy, poison oak, and poison sumac. Urushiol from these plants differs only slightly in structure; therefore, sensitization to one causes sensitization to all. There also is cross-reactivity between different members of the Anacardiaceae family, including Anacardium occidentale (tropical cashew nut), Mangifera indica (tropical mango tree), Ginkgo biloba (ginkgo tree), and Semecarpus anacardium (Indian marking nut tree).¹²

Poison ivy, poison oak, and poison sumac cause allergic contact dermatitis as a type IV hypersensitivity reaction. First, urushiol binds and penetrates the skin, where it is oxidized to quinone intermediates and bound to haptens. Then, the intermediates bind surface proteins on antigen-presenting cells, specifically Langerhans cells in the epidermis and dermis.⁵

Presentation of nonpeptide antigens, such as urushiol, to T cells requires expression of langerin (also known as CD207) and CD1a.¹⁶ Langerin is a C-type lectin that causes formation of Birbeck granules; CD1a is a major histocompatibility complex class I molecule found in Birbeck granules.^5,17 After Langerhans cells internalize and process the urushiol self-hapten neoantigen, it is presented to CD4⁺ T cells.⁶ These cells then expand to form circulating activated T-effector and T-memory lymphocytes.¹⁸

The molecular link that occurs between the hapten and carrier protein determines the response. When linked by an amino nucleophile, selective induction of T-effector cells ensues, resulting in allergic contact dermatitis. When linked by a sulfhydryl bond, selective induction of suppressor cells occurs, resulting in a reduced allergic contact dermatitis response.¹⁹ In the case of activation of T-effector cells, a cell-mediated cytotoxic immune response is generated that destroys epidermal cells and dermal vasculature.² The incidence and intensity of poison ivy sensitivity decline proportionally with age and the absence of continued exposure.²⁰

Preventive Action—Patients should be counseled that if contact between plant and skin occurs, it is important to remove contaminated clothing or objects and wash them with soap to prevent additional exposure.^14,21 Areas of the skin that made contact with the plant should be washed with water as soon as possible; after 30 minutes, urushiol has sufficiently penetrated to cause a reaction.² Forceful unidirectional washing with a damp washcloth and liquid dishwashing soap is recommended.²²

Several barrier creams are commercially available to help prevent absorption or to deactivate the urushiol antigen. These products are used widely by forestry workers and wildland firefighters.²³ One such barrier cream is bentoquatam (sold as various trade names), an organoclay compound made of quaternium-18 bentonite that interferes with absorption of the allergen by acting as a physical blocker.²⁴

Treatment

After Toxicodendron dermatitis develops, several treatments are available to help manage symptoms. Calamine lotion can be used to help dry weeping lesions.^25,26 Topical steroids can be used to help control pruritus and alleviate inflammation. High-potency topical corticosteroids such as clobetasol and mid-potency steroids such as triamcinolone can be used. Topical anesthetics (eg, benzocaine, pramoxine, benzyl alcohol) might provide symptomatic relief.^27,28

Oral antihistamines can allow for better sleep by providing sedation but do not target the pruritus of poison ivy dermatitis, which is not histamine mediated.^29,30 Systemic corticosteroids usually are considered in more severe dermatitis—when 20% or more of the body surface area is involved; blistering and itching are severe; or the face, hands, or genitalia are involved.^31,32

Clinical Uses

Therapeutic uses for poison ivy have been explored extensively. In 1892, Dakin³³ reported that ingestion of leaves by Native Americans reduced the incidence and severity of skin lesions after contact with poison ivy. Consumption of poison ivy was further studied by Epstein and colleagues³⁴ in 1974; they concluded that ingestion of a large amount of urushiol over a period of 3 months or longer may help with hyposensitization—but not complete desensitization—to contact with poison ivy. However, the risk for adverse effects is thought to outweigh benefits because ingestion can cause perianal dermatitis, mucocutaneous sequelae, and systemic contact dermatitis.²

Although the use of Toxicodendron plants in modern-day medicine is limited, development of a vaccine (immunotherapy) against Toxicodendron dermatitis offers an exciting opportunity for further research.

It is unsurprising that food frequently is thought to be the culprit behind an eczema flare, especially in infants. Indeed, it often is said that infants do only 3 things: eat, sleep, and poop.¹ For those unfortunate enough to develop the signs and symptoms of atopic dermatitis (AD), food quickly emerges as a potential culprit from the tiny pool of suspects, which is against a cultural backdrop of unprecedented focus on foods and food reactions.² The prevalence of food allergies in children, though admittedly fraught with methodological difficulties, is estimated to have more than doubled from 3.4% in 1999 to 7.6% in 2018.³ As expected, prevalence rates were higher among children with other atopic comorbidities including AD, with up to 50% of children with AD demonstrating convincing food allergy.⁴ It is easy to imagine a patient conflating these 2 entities and mistaking their correlation for causation. Thus, it follows that more than 90% of parents/guardians have reported that their children have had food-induced AD, and understandably—at least according to one study—75% of parents/guardians were found to have manipulated the diet in an attempt to manage the disease.^5,6

Patients and parents/guardians are not the only ones who have suspected food as a driving force in AD. An article in the British Medical Journal from the 1800s beautifully encapsulated the depth and duration of this quandary: “There is probably no subject in which more deeply rooted convictions have been held, not only in the profession but by the laity, than the connection between diet and disease, both as regards the causation and treatment of the latter.”⁷ Herein, a wide range of food reactions is examined to highlight evidence for the role of diet in AD, which may contradict what patients—and even some clinicians—believe.

No Easy Answers

A definitive statement that food allergy is not the root cause of AD would put this issue to rest, but such simplicity does not reflect the complex reality. First, we must agree on definitions for certain terms. What do we mean by food allergy? A broader category—adverse food reactions—covers a wide range of entities, some immune mediated and some not, including lactose intolerance, irritant contact dermatitis around the mouth, and even dermatitis herpetiformis (the cutaneous manifestation of celiac disease).⁸ Although the term food allergy often is used synonymously with adverse food reactions, the exact definition of a food allergy is specific: “adverse immune responses to food proteins that result in typical clinical symptoms.”⁸ The fact that many patients and even health care practitioners seem to frequently misapply this term makes it even more confusing. 

The current focus is on foods that could trigger a flare of AD, which clearly is a broader question than food allergy sensu stricto. It seems self-evident, for example, that if an infant with AD were to (messily) eat an acidic food such as an orange, a flare-up of AD around the mouth and on the cheeks and hands would be a forgone conclusion. Similar nonimmunologic scenarios unambiguously can occur with many foods, including citrus; corn; radish; mustard; garlic; onion; pineapple; and many spices, food additives, and preservatives.⁹ Clearly there are some scenarios whereby food could trigger an AD flare, and yet this more limited vignette generally is not what patients are referring to when suggesting that food is the root cause of their AD.

The Labyrinth of Testing for Food Allergies

Although there is no reliable method for testing for irritant dermatitis, understanding the other types of tests may help guide our thinking. Testing for IgE-mediated food allergies generally is done via an immunoenzymatic serum assay that can document sensitization to a food protein; however, this testing by itself is not sufficient to diagnose a clinical food allergy.¹⁰ Similarly, skin prick testing allows for intradermal administration of a food extract to evaluate for an urticarial reaction within 10 to 15 minutes. Although the sensitivity and specificity vary by age, population, and the specific allergen being tested, these are limited to immediate-type reactions and do not reflect the potential to drive an eczematous flare.

The gold standard, if there is one, is likely the double-blind, placebo-controlled food challenge (DBPCFC), ideally with a long enough observation period to capture later-occurring reactions such as an AD flare. However, given the nature of the test—having patients eat the foods of concern and then carefully following them for reactions—it remains time consuming, expensive, and labor intensive.¹¹ 

To further complicate matters, several unvalidated tests exist such as IgG testing, atopy patch testing, kinesiology, and hair and gastric juice analysis, which remain investigational but continue to be used and may further confuse patients and clinicians.¹²

It is useful to first separate out the classic IgE-mediated food allergy reactions that are common. In these immediate-type reactions, a person sensitized to a food protein will develop characteristic cutaneous and/or extracutaneous reactions such as urticaria, angioedema, and even anaphylaxis, usually within minutes of exposure. Although it is possible that an IgE-mediated reaction could trigger an AD flare—perhaps simply by causing pruritus, which could initiate the itch-scratch cycle—because of the near simultaneity with ingestion of the offending food and the often dramatic clinical presentations, such foods clearly do not represent “hidden” triggers for AD flares.³ The concept of food-triggered AD (FTAD) is crucial for thinking about foods that could result in true eczematous flares, which historically have been classified as early-type (<2 hours after food challenge) and late-type (≥2 hours after food challenge) reactions.^13,14 

A study of more than 1000 DBPCFCs performed in patients with AD was illustrative.¹⁵ Immediate reactions other than AD were fairly common and were observed in 40% of the food challenges compared to only 9% in the placebo group. These reactions included urticaria, angioedema, and gastrointestinal and respiratory tract symptoms. Immediate reactions of AD alone were exceedingly rare at only 0.7% and not significantly elevated compared to placebo. Just over 4% experienced both an immediate AD exacerbation along with other non-AD findings, which was significantly greater than placebo (P<.01). Although intermediate and late reactions manifesting as AD exacerbations did occur after food ingestion, they were rare (2.2% or less) and not significantly different from placebo. The authors concluded that an exacerbation of AD in the absence of other allergic symptoms in children was unlikely to be due to food,¹⁵ which is an important finding.

A recent retrospective review of 372 children with AD reported similar results.⁴ The authors defined FTAD in a different way; instead of showing a flare after a DBPCFC, they looked for “physician-noted sustained improvement in AD upon removal of a food (typically after 2–6-wk follow-up), to which the child was sensitized without any other changes in skin care.” Despite this fundamentally different approach, they similarly concluded that while food allergies were common, FTAD was relatively uncommon—found in 2% of those with mild AD, 6% of those with moderate AD, and 4% of those with severe AD.⁴ 

There are other ways that foods could contribute to disease flares, however, and one of the most compelling is that there may be broader concepts at play; perhaps some diets are not specifically driving the AD but rather are affecting inflammation in the body at large. Although somewhat speculative, there is evidence that some foods may simply be proinflammatory, working to exacerbate the disease outside of a specific mechanism, which has been seen in a variety of other conditions such as acne or rheumatoid arthritis.^16,17 To speculate further, it is possible that there may be a threshold effect such that when the AD is poorly controlled, certain factors such as inflammatory foods could lead to a flare, while when under better control, these same factors may not cause an effect.

Finally, it is important to also consider the emotional and/or psychological aspects related to food and diet. The power of the placebo in dietary change has been documented in several diseases, though this certainly is not to be dismissive of the patient’s symptoms; it seems reasonable that the very act of changing such a fundamental aspect of daily life could result in a placebo effect.^18,19 In the context of relapsing and remitting conditions such as AD, this effect may be magnified. A landmark study by Thompson and Hanifin²⁰ illustrates this possibility. The authors found that in 80% of cases in which patients were convinced that food was a major contributing factor to their AD, such concerns diminished markedly once better control of the eczema was achieved.²⁰

This brings us to what to do with an individual patient in the examination room. Because there is such widespread concern and discussion around this topic, it is important to at least briefly address it. If there are known food allergens that are being avoided, it is important to underscore the importance of continuing to avoid those foods, especially when there is actual evidence of true food allergy rather than sensitization alone. Historically, elimination diets often were recommended empirically, though more recent studies, meta-analyses, and guidance documents increasingly have recommended against them.³ In particular, there are major concerns for iatrogenic harm. 

First, heavily restricted diets may result in nutritional and/or caloric deficiencies that can be dangerous and lead to poor growth.²¹ Practices such as drinking unpasteurized milk can expose children to dangerous infections, while feeding them exclusively rice milk can lead to severe malnutrition.²² 

Second, there is a dawning realization that children with AD placed on elimination diets may actually develop true IgE-mediated allergies, including fatal anaphylaxis, to the excluded foods. In fact, one retrospective review of 298 patients with a history of AD and no prior immediate reactions found that 19% of patients developed new immediate-type hypersensitivity reactions after starting an elimination diet, presumably due to the loss of tolerance to these foods. A striking one-third of these reactions were classified as anaphylaxis, with cow’s milk and egg being the most common offenders.²³

It also is crucial to acknowledge that recommending sweeping lifestyle changes is not easy for patients, especially pediatric patients. Onerous dietary restrictions may add considerable stress, ironically a known trigger for AD itself. 

Finally, dietary modifications can be a distraction from conventional therapy and may result in treatment delays while the patient continues to experience uncontrolled symptoms of AD. 

Final Thoughts

Diet is intimately related to AD. Although the narrative continues to unfold in fascinating domains, such as the skin barrier and the microbiome, it is increasingly clear that these are intertwined and always have been. Despite the rarity of true food-triggered AD, the perception of dietary triggers is so widespread and addressing the topic is important and may help avoid unnecessary harm from unfounded extreme dietary changes. A recent multispecialty workgroup report on AD and food allergy succinctly summarized this as: “AD has many triggers and comorbidities, and food allergy is only one of the potential triggers and comorbid conditions. With regard to AD management, education and skin care are most important.”³ With proper testing, guidance, and both topical and systemic therapies, most AD can be brought under control, and for at least some patients, this may allay concerns about foods triggering their AD. 

It is unsurprising that food frequently is thought to be the culprit behind an eczema flare, especially in infants. Indeed, it often is said that infants do only 3 things: eat, sleep, and poop.¹ For those unfortunate enough to develop the signs and symptoms of atopic dermatitis (AD), food quickly emerges as a potential culprit from the tiny pool of suspects, which is against a cultural backdrop of unprecedented focus on foods and food reactions.² The prevalence of food allergies in children, though admittedly fraught with methodological difficulties, is estimated to have more than doubled from 3.4% in 1999 to 7.6% in 2018.³ As expected, prevalence rates were higher among children with other atopic comorbidities including AD, with up to 50% of children with AD demonstrating convincing food allergy.⁴ It is easy to imagine a patient conflating these 2 entities and mistaking their correlation for causation. Thus, it follows that more than 90% of parents/guardians have reported that their children have had food-induced AD, and understandably—at least according to one study—75% of parents/guardians were found to have manipulated the diet in an attempt to manage the disease.^5,6

Patients and parents/guardians are not the only ones who have suspected food as a driving force in AD. An article in the British Medical Journal from the 1800s beautifully encapsulated the depth and duration of this quandary: “There is probably no subject in which more deeply rooted convictions have been held, not only in the profession but by the laity, than the connection between diet and disease, both as regards the causation and treatment of the latter.”⁷ Herein, a wide range of food reactions is examined to highlight evidence for the role of diet in AD, which may contradict what patients—and even some clinicians—believe.

No Easy Answers

A definitive statement that food allergy is not the root cause of AD would put this issue to rest, but such simplicity does not reflect the complex reality. First, we must agree on definitions for certain terms. What do we mean by food allergy? A broader category—adverse food reactions—covers a wide range of entities, some immune mediated and some not, including lactose intolerance, irritant contact dermatitis around the mouth, and even dermatitis herpetiformis (the cutaneous manifestation of celiac disease).⁸ Although the term food allergy often is used synonymously with adverse food reactions, the exact definition of a food allergy is specific: “adverse immune responses to food proteins that result in typical clinical symptoms.”⁸ The fact that many patients and even health care practitioners seem to frequently misapply this term makes it even more confusing. 

The current focus is on foods that could trigger a flare of AD, which clearly is a broader question than food allergy sensu stricto. It seems self-evident, for example, that if an infant with AD were to (messily) eat an acidic food such as an orange, a flare-up of AD around the mouth and on the cheeks and hands would be a forgone conclusion. Similar nonimmunologic scenarios unambiguously can occur with many foods, including citrus; corn; radish; mustard; garlic; onion; pineapple; and many spices, food additives, and preservatives.⁹ Clearly there are some scenarios whereby food could trigger an AD flare, and yet this more limited vignette generally is not what patients are referring to when suggesting that food is the root cause of their AD.

The Labyrinth of Testing for Food Allergies

Although there is no reliable method for testing for irritant dermatitis, understanding the other types of tests may help guide our thinking. Testing for IgE-mediated food allergies generally is done via an immunoenzymatic serum assay that can document sensitization to a food protein; however, this testing by itself is not sufficient to diagnose a clinical food allergy.¹⁰ Similarly, skin prick testing allows for intradermal administration of a food extract to evaluate for an urticarial reaction within 10 to 15 minutes. Although the sensitivity and specificity vary by age, population, and the specific allergen being tested, these are limited to immediate-type reactions and do not reflect the potential to drive an eczematous flare.

The gold standard, if there is one, is likely the double-blind, placebo-controlled food challenge (DBPCFC), ideally with a long enough observation period to capture later-occurring reactions such as an AD flare. However, given the nature of the test—having patients eat the foods of concern and then carefully following them for reactions—it remains time consuming, expensive, and labor intensive.¹¹ 

To further complicate matters, several unvalidated tests exist such as IgG testing, atopy patch testing, kinesiology, and hair and gastric juice analysis, which remain investigational but continue to be used and may further confuse patients and clinicians.¹²

It is useful to first separate out the classic IgE-mediated food allergy reactions that are common. In these immediate-type reactions, a person sensitized to a food protein will develop characteristic cutaneous and/or extracutaneous reactions such as urticaria, angioedema, and even anaphylaxis, usually within minutes of exposure. Although it is possible that an IgE-mediated reaction could trigger an AD flare—perhaps simply by causing pruritus, which could initiate the itch-scratch cycle—because of the near simultaneity with ingestion of the offending food and the often dramatic clinical presentations, such foods clearly do not represent “hidden” triggers for AD flares.³ The concept of food-triggered AD (FTAD) is crucial for thinking about foods that could result in true eczematous flares, which historically have been classified as early-type (<2 hours after food challenge) and late-type (≥2 hours after food challenge) reactions.^13,14 

A study of more than 1000 DBPCFCs performed in patients with AD was illustrative.¹⁵ Immediate reactions other than AD were fairly common and were observed in 40% of the food challenges compared to only 9% in the placebo group. These reactions included urticaria, angioedema, and gastrointestinal and respiratory tract symptoms. Immediate reactions of AD alone were exceedingly rare at only 0.7% and not significantly elevated compared to placebo. Just over 4% experienced both an immediate AD exacerbation along with other non-AD findings, which was significantly greater than placebo (P<.01). Although intermediate and late reactions manifesting as AD exacerbations did occur after food ingestion, they were rare (2.2% or less) and not significantly different from placebo. The authors concluded that an exacerbation of AD in the absence of other allergic symptoms in children was unlikely to be due to food,¹⁵ which is an important finding.

A recent retrospective review of 372 children with AD reported similar results.⁴ The authors defined FTAD in a different way; instead of showing a flare after a DBPCFC, they looked for “physician-noted sustained improvement in AD upon removal of a food (typically after 2–6-wk follow-up), to which the child was sensitized without any other changes in skin care.” Despite this fundamentally different approach, they similarly concluded that while food allergies were common, FTAD was relatively uncommon—found in 2% of those with mild AD, 6% of those with moderate AD, and 4% of those with severe AD.⁴ 

There are other ways that foods could contribute to disease flares, however, and one of the most compelling is that there may be broader concepts at play; perhaps some diets are not specifically driving the AD but rather are affecting inflammation in the body at large. Although somewhat speculative, there is evidence that some foods may simply be proinflammatory, working to exacerbate the disease outside of a specific mechanism, which has been seen in a variety of other conditions such as acne or rheumatoid arthritis.^16,17 To speculate further, it is possible that there may be a threshold effect such that when the AD is poorly controlled, certain factors such as inflammatory foods could lead to a flare, while when under better control, these same factors may not cause an effect.

Finally, it is important to also consider the emotional and/or psychological aspects related to food and diet. The power of the placebo in dietary change has been documented in several diseases, though this certainly is not to be dismissive of the patient’s symptoms; it seems reasonable that the very act of changing such a fundamental aspect of daily life could result in a placebo effect.^18,19 In the context of relapsing and remitting conditions such as AD, this effect may be magnified. A landmark study by Thompson and Hanifin²⁰ illustrates this possibility. The authors found that in 80% of cases in which patients were convinced that food was a major contributing factor to their AD, such concerns diminished markedly once better control of the eczema was achieved.²⁰

This brings us to what to do with an individual patient in the examination room. Because there is such widespread concern and discussion around this topic, it is important to at least briefly address it. If there are known food allergens that are being avoided, it is important to underscore the importance of continuing to avoid those foods, especially when there is actual evidence of true food allergy rather than sensitization alone. Historically, elimination diets often were recommended empirically, though more recent studies, meta-analyses, and guidance documents increasingly have recommended against them.³ In particular, there are major concerns for iatrogenic harm. 

First, heavily restricted diets may result in nutritional and/or caloric deficiencies that can be dangerous and lead to poor growth.²¹ Practices such as drinking unpasteurized milk can expose children to dangerous infections, while feeding them exclusively rice milk can lead to severe malnutrition.²² 

Second, there is a dawning realization that children with AD placed on elimination diets may actually develop true IgE-mediated allergies, including fatal anaphylaxis, to the excluded foods. In fact, one retrospective review of 298 patients with a history of AD and no prior immediate reactions found that 19% of patients developed new immediate-type hypersensitivity reactions after starting an elimination diet, presumably due to the loss of tolerance to these foods. A striking one-third of these reactions were classified as anaphylaxis, with cow’s milk and egg being the most common offenders.²³

It also is crucial to acknowledge that recommending sweeping lifestyle changes is not easy for patients, especially pediatric patients. Onerous dietary restrictions may add considerable stress, ironically a known trigger for AD itself. 

Finally, dietary modifications can be a distraction from conventional therapy and may result in treatment delays while the patient continues to experience uncontrolled symptoms of AD. 

Final Thoughts

Diet is intimately related to AD. Although the narrative continues to unfold in fascinating domains, such as the skin barrier and the microbiome, it is increasingly clear that these are intertwined and always have been. Despite the rarity of true food-triggered AD, the perception of dietary triggers is so widespread and addressing the topic is important and may help avoid unnecessary harm from unfounded extreme dietary changes. A recent multispecialty workgroup report on AD and food allergy succinctly summarized this as: “AD has many triggers and comorbidities, and food allergy is only one of the potential triggers and comorbid conditions. With regard to AD management, education and skin care are most important.”³ With proper testing, guidance, and both topical and systemic therapies, most AD can be brought under control, and for at least some patients, this may allay concerns about foods triggering their AD. 

It is unsurprising that food frequently is thought to be the culprit behind an eczema flare, especially in infants. Indeed, it often is said that infants do only 3 things: eat, sleep, and poop.¹ For those unfortunate enough to develop the signs and symptoms of atopic dermatitis (AD), food quickly emerges as a potential culprit from the tiny pool of suspects, which is against a cultural backdrop of unprecedented focus on foods and food reactions.² The prevalence of food allergies in children, though admittedly fraught with methodological difficulties, is estimated to have more than doubled from 3.4% in 1999 to 7.6% in 2018.³ As expected, prevalence rates were higher among children with other atopic comorbidities including AD, with up to 50% of children with AD demonstrating convincing food allergy.⁴ It is easy to imagine a patient conflating these 2 entities and mistaking their correlation for causation. Thus, it follows that more than 90% of parents/guardians have reported that their children have had food-induced AD, and understandably—at least according to one study—75% of parents/guardians were found to have manipulated the diet in an attempt to manage the disease.^5,6

Patients and parents/guardians are not the only ones who have suspected food as a driving force in AD. An article in the British Medical Journal from the 1800s beautifully encapsulated the depth and duration of this quandary: “There is probably no subject in which more deeply rooted convictions have been held, not only in the profession but by the laity, than the connection between diet and disease, both as regards the causation and treatment of the latter.”⁷ Herein, a wide range of food reactions is examined to highlight evidence for the role of diet in AD, which may contradict what patients—and even some clinicians—believe.

No Easy Answers

A definitive statement that food allergy is not the root cause of AD would put this issue to rest, but such simplicity does not reflect the complex reality. First, we must agree on definitions for certain terms. What do we mean by food allergy? A broader category—adverse food reactions—covers a wide range of entities, some immune mediated and some not, including lactose intolerance, irritant contact dermatitis around the mouth, and even dermatitis herpetiformis (the cutaneous manifestation of celiac disease).⁸ Although the term food allergy often is used synonymously with adverse food reactions, the exact definition of a food allergy is specific: “adverse immune responses to food proteins that result in typical clinical symptoms.”⁸ The fact that many patients and even health care practitioners seem to frequently misapply this term makes it even more confusing. 

The current focus is on foods that could trigger a flare of AD, which clearly is a broader question than food allergy sensu stricto. It seems self-evident, for example, that if an infant with AD were to (messily) eat an acidic food such as an orange, a flare-up of AD around the mouth and on the cheeks and hands would be a forgone conclusion. Similar nonimmunologic scenarios unambiguously can occur with many foods, including citrus; corn; radish; mustard; garlic; onion; pineapple; and many spices, food additives, and preservatives.⁹ Clearly there are some scenarios whereby food could trigger an AD flare, and yet this more limited vignette generally is not what patients are referring to when suggesting that food is the root cause of their AD.

The Labyrinth of Testing for Food Allergies

Although there is no reliable method for testing for irritant dermatitis, understanding the other types of tests may help guide our thinking. Testing for IgE-mediated food allergies generally is done via an immunoenzymatic serum assay that can document sensitization to a food protein; however, this testing by itself is not sufficient to diagnose a clinical food allergy.¹⁰ Similarly, skin prick testing allows for intradermal administration of a food extract to evaluate for an urticarial reaction within 10 to 15 minutes. Although the sensitivity and specificity vary by age, population, and the specific allergen being tested, these are limited to immediate-type reactions and do not reflect the potential to drive an eczematous flare.

The gold standard, if there is one, is likely the double-blind, placebo-controlled food challenge (DBPCFC), ideally with a long enough observation period to capture later-occurring reactions such as an AD flare. However, given the nature of the test—having patients eat the foods of concern and then carefully following them for reactions—it remains time consuming, expensive, and labor intensive.¹¹ 

To further complicate matters, several unvalidated tests exist such as IgG testing, atopy patch testing, kinesiology, and hair and gastric juice analysis, which remain investigational but continue to be used and may further confuse patients and clinicians.¹²

It is useful to first separate out the classic IgE-mediated food allergy reactions that are common. In these immediate-type reactions, a person sensitized to a food protein will develop characteristic cutaneous and/or extracutaneous reactions such as urticaria, angioedema, and even anaphylaxis, usually within minutes of exposure. Although it is possible that an IgE-mediated reaction could trigger an AD flare—perhaps simply by causing pruritus, which could initiate the itch-scratch cycle—because of the near simultaneity with ingestion of the offending food and the often dramatic clinical presentations, such foods clearly do not represent “hidden” triggers for AD flares.³ The concept of food-triggered AD (FTAD) is crucial for thinking about foods that could result in true eczematous flares, which historically have been classified as early-type (<2 hours after food challenge) and late-type (≥2 hours after food challenge) reactions.^13,14 

A study of more than 1000 DBPCFCs performed in patients with AD was illustrative.¹⁵ Immediate reactions other than AD were fairly common and were observed in 40% of the food challenges compared to only 9% in the placebo group. These reactions included urticaria, angioedema, and gastrointestinal and respiratory tract symptoms. Immediate reactions of AD alone were exceedingly rare at only 0.7% and not significantly elevated compared to placebo. Just over 4% experienced both an immediate AD exacerbation along with other non-AD findings, which was significantly greater than placebo (P<.01). Although intermediate and late reactions manifesting as AD exacerbations did occur after food ingestion, they were rare (2.2% or less) and not significantly different from placebo. The authors concluded that an exacerbation of AD in the absence of other allergic symptoms in children was unlikely to be due to food,¹⁵ which is an important finding.

A recent retrospective review of 372 children with AD reported similar results.⁴ The authors defined FTAD in a different way; instead of showing a flare after a DBPCFC, they looked for “physician-noted sustained improvement in AD upon removal of a food (typically after 2–6-wk follow-up), to which the child was sensitized without any other changes in skin care.” Despite this fundamentally different approach, they similarly concluded that while food allergies were common, FTAD was relatively uncommon—found in 2% of those with mild AD, 6% of those with moderate AD, and 4% of those with severe AD.⁴ 

There are other ways that foods could contribute to disease flares, however, and one of the most compelling is that there may be broader concepts at play; perhaps some diets are not specifically driving the AD but rather are affecting inflammation in the body at large. Although somewhat speculative, there is evidence that some foods may simply be proinflammatory, working to exacerbate the disease outside of a specific mechanism, which has been seen in a variety of other conditions such as acne or rheumatoid arthritis.^16,17 To speculate further, it is possible that there may be a threshold effect such that when the AD is poorly controlled, certain factors such as inflammatory foods could lead to a flare, while when under better control, these same factors may not cause an effect.

Finally, it is important to also consider the emotional and/or psychological aspects related to food and diet. The power of the placebo in dietary change has been documented in several diseases, though this certainly is not to be dismissive of the patient’s symptoms; it seems reasonable that the very act of changing such a fundamental aspect of daily life could result in a placebo effect.^18,19 In the context of relapsing and remitting conditions such as AD, this effect may be magnified. A landmark study by Thompson and Hanifin²⁰ illustrates this possibility. The authors found that in 80% of cases in which patients were convinced that food was a major contributing factor to their AD, such concerns diminished markedly once better control of the eczema was achieved.²⁰

This brings us to what to do with an individual patient in the examination room. Because there is such widespread concern and discussion around this topic, it is important to at least briefly address it. If there are known food allergens that are being avoided, it is important to underscore the importance of continuing to avoid those foods, especially when there is actual evidence of true food allergy rather than sensitization alone. Historically, elimination diets often were recommended empirically, though more recent studies, meta-analyses, and guidance documents increasingly have recommended against them.³ In particular, there are major concerns for iatrogenic harm. 

First, heavily restricted diets may result in nutritional and/or caloric deficiencies that can be dangerous and lead to poor growth.²¹ Practices such as drinking unpasteurized milk can expose children to dangerous infections, while feeding them exclusively rice milk can lead to severe malnutrition.²² 

Second, there is a dawning realization that children with AD placed on elimination diets may actually develop true IgE-mediated allergies, including fatal anaphylaxis, to the excluded foods. In fact, one retrospective review of 298 patients with a history of AD and no prior immediate reactions found that 19% of patients developed new immediate-type hypersensitivity reactions after starting an elimination diet, presumably due to the loss of tolerance to these foods. A striking one-third of these reactions were classified as anaphylaxis, with cow’s milk and egg being the most common offenders.²³

It also is crucial to acknowledge that recommending sweeping lifestyle changes is not easy for patients, especially pediatric patients. Onerous dietary restrictions may add considerable stress, ironically a known trigger for AD itself. 

Finally, dietary modifications can be a distraction from conventional therapy and may result in treatment delays while the patient continues to experience uncontrolled symptoms of AD. 

Final Thoughts

Diet is intimately related to AD. Although the narrative continues to unfold in fascinating domains, such as the skin barrier and the microbiome, it is increasingly clear that these are intertwined and always have been. Despite the rarity of true food-triggered AD, the perception of dietary triggers is so widespread and addressing the topic is important and may help avoid unnecessary harm from unfounded extreme dietary changes. A recent multispecialty workgroup report on AD and food allergy succinctly summarized this as: “AD has many triggers and comorbidities, and food allergy is only one of the potential triggers and comorbid conditions. With regard to AD management, education and skin care are most important.”³ With proper testing, guidance, and both topical and systemic therapies, most AD can be brought under control, and for at least some patients, this may allay concerns about foods triggering their AD. 

In an age of changing climate and emerging global pandemics, the ability of residency programs to prepare for and adapt to potential disasters may be paramount in preserving the training of physicians. The current literature regarding residency program disaster preparedness, which focuses predominantly on hurricanes and COVID-19,^1-8 is lacking in recommendations specific to dermatology residency programs. Likewise, the Accreditation Council for Graduate Medical Education (ACGME) guidelines⁹ do not address dermatology-specific concerns in disaster preparedness or response. Herein, we propose recommendations to mitigate the impact of various types of disasters on dermatology residency programs and their trainees with regard to resident safety and wellness, resident education, and patient care (Table).

Resident Safety and Wellness

Role of the Program Director—The role of the program director is critical, serving as a figure of structure and reassurance.^4,7,10 Once concern of disaster arises, the program director should contact the Designated Institutional Official (DIO) to express concerns about possible disruptions to resident training. The DIO should then contact the ACGME within 10 days to report the disaster and submit a request for emergency (eg, pandemic) or extraordinary circumstances (eg, natural disaster) categorization.^4,9 Program directors should promptly prepare plans for program reconfiguration and resident transfers in alignment with ACGME requirements to maintain evaluation and completion of core competencies of training during disasters.⁹ Program directors should prioritize the safety of trainees during the immediate threat with clear guidelines on sheltering, evacuations, or quarantines; a timeline of program recovery based on communication with residents, faculty, and administration should then be established.^10,11

Communication—Establishing a strong line of communication between program directors and residents is paramount. Collection of emergency noninstitutional contact information, establishment of a centralized website for information dissemination, use of noninstitutional email and proxy servers outside of the location of impact, social media updates, on-site use of 2-way radios, and program-wide conference calls when possible should be strongly considered as part of the disaster response.^2-4,12,13

Resident Accommodations and Mental Health—If training is disrupted, residents should be reassured of continued access to salary, housing, food, or other resources as necessary.^3,4,11 There should be clear contingency plans if residents need to leave the program for extended periods of time due to injury, illness, or personal circumstances. Although relevant in all types of disasters, resident mental health and response to trauma also must be addressed. Access to counseling, morale-building opportunities (eg, resident social events), and screening for depression or posttraumatic stress disorder may help promote well-being among residents following traumatic events.¹⁴

Resident Education

Participation in Disaster Relief—Residents may seek to aid in the disaster response, which may prove challenging in the setting of programs with high patient volume.⁴ In coordination with the ACGME and graduate medical education governing bodies, program directors should consider how residents may fulfill dermatology training requirements in conjunction with disaster relief efforts, such as working in an inpatient setting or providing wound care.¹⁰

Continued Didactic Education—The use of online learning and conference calls for continuing the dermatology curriculum is an efficient means to maintaining resident education when meeting in person poses risks to residents.¹⁵ Projections of microscopy images, clinical photographs, or other instructional materials allow for continued instruction on resident examination, histopathology, and diagnostic skills.

Continued Clinical Training—If the home institution cannot support the operation of dermatology clinics, residents should be guaranteed continued training at other institutions. Agreements with other dermatology programs, community hospitals, or private dermatology practices should be established in advance, with consideration given to the number of residents a program can support, funding transfers, and credentialing requirements.^2,4,5

Prolonged Disruptions—Nonessential departments of medical institutions may cease to function during war or mass casualty disasters, and it may be unsafe to send dermatology residents to other institutions or clinical areas. If the threat is prolonged, programs may need to consider allowing current residents a longer duration of training despite potential overlap with incoming dermatology residents.⁷

Patient Care

Disruptions to Clinic Operations—Regarding threats of violence, dangerous exposures, or natural disasters, there should be clear guidelines on sheltering in the clinical setting or stabilizing patients during a procedure.¹¹ Equipment used by residents such as laptops, microscopes, and treatment devices (eg, lasers) should be stored in weather-safe locations that would not be notably impacted by moisture or structural damage to the clinic building. If electricity or internet access are compromised, paper medical records should be available to residents to continue clinical operations. Electronic health records used by residents should regularly be backed up on remote servers or cloud storage to allow continued access to patient health information if on-site servers are not functional.¹² If disruptions are prolonged, residency program administration should coordinate with the institution to ensure there is adequate supply and storage of medications (eg, lidocaine, botulinum toxin) as well as a continued means of delivering biologic medications to patients and an ability to obtain laboratory or dermatopathology services.

In-Person Appointments vs Telemedicine—There are benefits to both residency training and patient care when physicians are able to perform in-person examinations, biopsies, and in-office treatments.¹⁶ Programs should ensure an adequate supply of personal protective equipment to continue in-office appointments, vaccinations, and medical care if a resident or other members of the team are exposed to an infectious disease.⁷ If in-person appointments are limited or impossible, telemedicine capabilities may still allow residents to meet program requirements.^7,10,15 However, reduced patient volume due to decreased elective visits or procedures may complicate the fulfillment of clinical requirements, which may need to be adjusted in the wake of a disaster.⁷

Use of Immunosuppressive Therapies—Residency programs should address the risks of prescribing immunosuppressive therapies (eg, biologics) during an infectious threat with their residents and encourage trainees to counsel patients on the importance of preventative measures to reduce risks for severe infection.¹⁷

Final Thoughts

Disasters often are unpredictable. Dermatology residency programs will not be immune to the future impacts of climate change, violent threats, or emerging pandemics. Lessons from prior natural disasters and the COVID-19 pandemic have made it clear that program directors need to be adaptable. If they plan proactively, comprehensive disaster preparedness can help to maintain high-quality training of dermatology residents in the face of extraordinary and challenging circumstances, promoting the resiliency and sustainability of graduate medical education.

In an age of changing climate and emerging global pandemics, the ability of residency programs to prepare for and adapt to potential disasters may be paramount in preserving the training of physicians. The current literature regarding residency program disaster preparedness, which focuses predominantly on hurricanes and COVID-19,^1-8 is lacking in recommendations specific to dermatology residency programs. Likewise, the Accreditation Council for Graduate Medical Education (ACGME) guidelines⁹ do not address dermatology-specific concerns in disaster preparedness or response. Herein, we propose recommendations to mitigate the impact of various types of disasters on dermatology residency programs and their trainees with regard to resident safety and wellness, resident education, and patient care (Table).

Resident Safety and Wellness

Role of the Program Director—The role of the program director is critical, serving as a figure of structure and reassurance.^4,7,10 Once concern of disaster arises, the program director should contact the Designated Institutional Official (DIO) to express concerns about possible disruptions to resident training. The DIO should then contact the ACGME within 10 days to report the disaster and submit a request for emergency (eg, pandemic) or extraordinary circumstances (eg, natural disaster) categorization.^4,9 Program directors should promptly prepare plans for program reconfiguration and resident transfers in alignment with ACGME requirements to maintain evaluation and completion of core competencies of training during disasters.⁹ Program directors should prioritize the safety of trainees during the immediate threat with clear guidelines on sheltering, evacuations, or quarantines; a timeline of program recovery based on communication with residents, faculty, and administration should then be established.^10,11

Communication—Establishing a strong line of communication between program directors and residents is paramount. Collection of emergency noninstitutional contact information, establishment of a centralized website for information dissemination, use of noninstitutional email and proxy servers outside of the location of impact, social media updates, on-site use of 2-way radios, and program-wide conference calls when possible should be strongly considered as part of the disaster response.^2-4,12,13

Resident Accommodations and Mental Health—If training is disrupted, residents should be reassured of continued access to salary, housing, food, or other resources as necessary.^3,4,11 There should be clear contingency plans if residents need to leave the program for extended periods of time due to injury, illness, or personal circumstances. Although relevant in all types of disasters, resident mental health and response to trauma also must be addressed. Access to counseling, morale-building opportunities (eg, resident social events), and screening for depression or posttraumatic stress disorder may help promote well-being among residents following traumatic events.¹⁴

Resident Education

Participation in Disaster Relief—Residents may seek to aid in the disaster response, which may prove challenging in the setting of programs with high patient volume.⁴ In coordination with the ACGME and graduate medical education governing bodies, program directors should consider how residents may fulfill dermatology training requirements in conjunction with disaster relief efforts, such as working in an inpatient setting or providing wound care.¹⁰

Continued Didactic Education—The use of online learning and conference calls for continuing the dermatology curriculum is an efficient means to maintaining resident education when meeting in person poses risks to residents.¹⁵ Projections of microscopy images, clinical photographs, or other instructional materials allow for continued instruction on resident examination, histopathology, and diagnostic skills.

Continued Clinical Training—If the home institution cannot support the operation of dermatology clinics, residents should be guaranteed continued training at other institutions. Agreements with other dermatology programs, community hospitals, or private dermatology practices should be established in advance, with consideration given to the number of residents a program can support, funding transfers, and credentialing requirements.^2,4,5

Prolonged Disruptions—Nonessential departments of medical institutions may cease to function during war or mass casualty disasters, and it may be unsafe to send dermatology residents to other institutions or clinical areas. If the threat is prolonged, programs may need to consider allowing current residents a longer duration of training despite potential overlap with incoming dermatology residents.⁷

Patient Care

Disruptions to Clinic Operations—Regarding threats of violence, dangerous exposures, or natural disasters, there should be clear guidelines on sheltering in the clinical setting or stabilizing patients during a procedure.¹¹ Equipment used by residents such as laptops, microscopes, and treatment devices (eg, lasers) should be stored in weather-safe locations that would not be notably impacted by moisture or structural damage to the clinic building. If electricity or internet access are compromised, paper medical records should be available to residents to continue clinical operations. Electronic health records used by residents should regularly be backed up on remote servers or cloud storage to allow continued access to patient health information if on-site servers are not functional.¹² If disruptions are prolonged, residency program administration should coordinate with the institution to ensure there is adequate supply and storage of medications (eg, lidocaine, botulinum toxin) as well as a continued means of delivering biologic medications to patients and an ability to obtain laboratory or dermatopathology services.

In-Person Appointments vs Telemedicine—There are benefits to both residency training and patient care when physicians are able to perform in-person examinations, biopsies, and in-office treatments.¹⁶ Programs should ensure an adequate supply of personal protective equipment to continue in-office appointments, vaccinations, and medical care if a resident or other members of the team are exposed to an infectious disease.⁷ If in-person appointments are limited or impossible, telemedicine capabilities may still allow residents to meet program requirements.^7,10,15 However, reduced patient volume due to decreased elective visits or procedures may complicate the fulfillment of clinical requirements, which may need to be adjusted in the wake of a disaster.⁷

Use of Immunosuppressive Therapies—Residency programs should address the risks of prescribing immunosuppressive therapies (eg, biologics) during an infectious threat with their residents and encourage trainees to counsel patients on the importance of preventative measures to reduce risks for severe infection.¹⁷

Final Thoughts

Disasters often are unpredictable. Dermatology residency programs will not be immune to the future impacts of climate change, violent threats, or emerging pandemics. Lessons from prior natural disasters and the COVID-19 pandemic have made it clear that program directors need to be adaptable. If they plan proactively, comprehensive disaster preparedness can help to maintain high-quality training of dermatology residents in the face of extraordinary and challenging circumstances, promoting the resiliency and sustainability of graduate medical education.

In an age of changing climate and emerging global pandemics, the ability of residency programs to prepare for and adapt to potential disasters may be paramount in preserving the training of physicians. The current literature regarding residency program disaster preparedness, which focuses predominantly on hurricanes and COVID-19,^1-8 is lacking in recommendations specific to dermatology residency programs. Likewise, the Accreditation Council for Graduate Medical Education (ACGME) guidelines⁹ do not address dermatology-specific concerns in disaster preparedness or response. Herein, we propose recommendations to mitigate the impact of various types of disasters on dermatology residency programs and their trainees with regard to resident safety and wellness, resident education, and patient care (Table).

Resident Safety and Wellness

Role of the Program Director—The role of the program director is critical, serving as a figure of structure and reassurance.^4,7,10 Once concern of disaster arises, the program director should contact the Designated Institutional Official (DIO) to express concerns about possible disruptions to resident training. The DIO should then contact the ACGME within 10 days to report the disaster and submit a request for emergency (eg, pandemic) or extraordinary circumstances (eg, natural disaster) categorization.^4,9 Program directors should promptly prepare plans for program reconfiguration and resident transfers in alignment with ACGME requirements to maintain evaluation and completion of core competencies of training during disasters.⁹ Program directors should prioritize the safety of trainees during the immediate threat with clear guidelines on sheltering, evacuations, or quarantines; a timeline of program recovery based on communication with residents, faculty, and administration should then be established.^10,11

Communication—Establishing a strong line of communication between program directors and residents is paramount. Collection of emergency noninstitutional contact information, establishment of a centralized website for information dissemination, use of noninstitutional email and proxy servers outside of the location of impact, social media updates, on-site use of 2-way radios, and program-wide conference calls when possible should be strongly considered as part of the disaster response.^2-4,12,13

Resident Accommodations and Mental Health—If training is disrupted, residents should be reassured of continued access to salary, housing, food, or other resources as necessary.^3,4,11 There should be clear contingency plans if residents need to leave the program for extended periods of time due to injury, illness, or personal circumstances. Although relevant in all types of disasters, resident mental health and response to trauma also must be addressed. Access to counseling, morale-building opportunities (eg, resident social events), and screening for depression or posttraumatic stress disorder may help promote well-being among residents following traumatic events.¹⁴

Resident Education

Participation in Disaster Relief—Residents may seek to aid in the disaster response, which may prove challenging in the setting of programs with high patient volume.⁴ In coordination with the ACGME and graduate medical education governing bodies, program directors should consider how residents may fulfill dermatology training requirements in conjunction with disaster relief efforts, such as working in an inpatient setting or providing wound care.¹⁰

Continued Didactic Education—The use of online learning and conference calls for continuing the dermatology curriculum is an efficient means to maintaining resident education when meeting in person poses risks to residents.¹⁵ Projections of microscopy images, clinical photographs, or other instructional materials allow for continued instruction on resident examination, histopathology, and diagnostic skills.

Continued Clinical Training—If the home institution cannot support the operation of dermatology clinics, residents should be guaranteed continued training at other institutions. Agreements with other dermatology programs, community hospitals, or private dermatology practices should be established in advance, with consideration given to the number of residents a program can support, funding transfers, and credentialing requirements.^2,4,5

Prolonged Disruptions—Nonessential departments of medical institutions may cease to function during war or mass casualty disasters, and it may be unsafe to send dermatology residents to other institutions or clinical areas. If the threat is prolonged, programs may need to consider allowing current residents a longer duration of training despite potential overlap with incoming dermatology residents.⁷

Patient Care

Disruptions to Clinic Operations—Regarding threats of violence, dangerous exposures, or natural disasters, there should be clear guidelines on sheltering in the clinical setting or stabilizing patients during a procedure.¹¹ Equipment used by residents such as laptops, microscopes, and treatment devices (eg, lasers) should be stored in weather-safe locations that would not be notably impacted by moisture or structural damage to the clinic building. If electricity or internet access are compromised, paper medical records should be available to residents to continue clinical operations. Electronic health records used by residents should regularly be backed up on remote servers or cloud storage to allow continued access to patient health information if on-site servers are not functional.¹² If disruptions are prolonged, residency program administration should coordinate with the institution to ensure there is adequate supply and storage of medications (eg, lidocaine, botulinum toxin) as well as a continued means of delivering biologic medications to patients and an ability to obtain laboratory or dermatopathology services.

In-Person Appointments vs Telemedicine—There are benefits to both residency training and patient care when physicians are able to perform in-person examinations, biopsies, and in-office treatments.¹⁶ Programs should ensure an adequate supply of personal protective equipment to continue in-office appointments, vaccinations, and medical care if a resident or other members of the team are exposed to an infectious disease.⁷ If in-person appointments are limited or impossible, telemedicine capabilities may still allow residents to meet program requirements.^7,10,15 However, reduced patient volume due to decreased elective visits or procedures may complicate the fulfillment of clinical requirements, which may need to be adjusted in the wake of a disaster.⁷

Use of Immunosuppressive Therapies—Residency programs should address the risks of prescribing immunosuppressive therapies (eg, biologics) during an infectious threat with their residents and encourage trainees to counsel patients on the importance of preventative measures to reduce risks for severe infection.¹⁷

Final Thoughts

Disasters often are unpredictable. Dermatology residency programs will not be immune to the future impacts of climate change, violent threats, or emerging pandemics. Lessons from prior natural disasters and the COVID-19 pandemic have made it clear that program directors need to be adaptable. If they plan proactively, comprehensive disaster preparedness can help to maintain high-quality training of dermatology residents in the face of extraordinary and challenging circumstances, promoting the resiliency and sustainability of graduate medical education.

Practice Gap

A male patient presented with 2 concerning lesions, which histopathology revealed were invasive squamous cell carcinoma (SCC) on the right medial chest and SCC in situ on the right upper scapular region. Both were treated with wide local excision; margins were clear in our office the same day.

This case highlighted a practice gap in postoperative care. Two factors posed a challenge to proper postoperative wound care for our patient:

• Because of the high risk of transmission of SARS-CoV-2, the patient hoped to limit exposure by avoiding an office visit to remove the bandage.

• The patient did not have someone at home to serve as an immediate support system, which made it impossible for him to rely on others for postoperative wound care.

Previously, the patient had to ask a friend to remove a bandage for melanoma in situ on the inner aspect of the left upper arm. Therefore, after this procedure, the patient asked if the bandage could be fashioned in a manner that would allow him to remove it without assistance (Figure 1).

Technique

In constructing a bandage that is easier to remove, some necessary pressure that is provided by the bandage often is sacrificed by making it looser. Considering that our patient had moderate bleeding during the procedure—in part because he took low-dose aspirin (81 mg/d)—it was important to maintain firm pressure under the bandage postoperatively to help prevent untoward bleeding. Furthermore, because of the location of the treated site and the patient’s limited range of motion, it was not feasible for him to reach the area on the scapula and remove the bandage.¹

For easy self-removal, we designed a bandage with a pull tab that was within the patient’s reach. Suitable materials for the pull tab bandage included surgical tape, bandaging tape with adequate stretch, sterile nonadhesive gauze, fenestrated surgical gauze, and a topical emollient such as petroleum jelly or antibacterial ointment.

To clean the site and decrease the amount of oil that would reduce the effectiveness of the adhesive, the wound was prepared with 70% alcohol. The site was then treated with petroleum jelly.

Next, we designed 2 pull tab bandage prototypes that allowed easy self-removal. For both prototypes, sterile nonadhesive gauze was applied to the wound along with folded and fenestrated gauze, which provided pressure. We used prototype #1 in our patient, and prototype #2 was demonstrated as an option.

Prototype #1—We created 2 tabs—each 2-feet long—using bandaging tape that was folded on itself once horizontally (Figure 2). The tabs were aligned on either side of the wound, the tops of which sat approximately 2 inches above the top of the first layer of adhesive bandage. An initial layer of adhesive surgical dressing was applied to cover the wound; 1 inch of the dressing was left exposed on the top of each tab. In addition, there were 2 “feet” running on the bottom.

The tops of the tabs were folded back over the adhesive tape, creating a type of “hook.” An additional final layer of adhesive tape was applied to ensure adequate pressure on the surgical site.

The patient was instructed to remove the bandage 2 days after the procedure. The outcome was qualified through a 3-day postoperative telephone call. The patient was asked about postoperative pain and his level of satisfaction with treatment. He was asked if he had any changes such as bleeding, swelling, signs of infection, or increased pain in the days after surgery or perceived postoperative complications, such as irritation. We asked the patient about the relative ease of removing the bandage and if removal was painful. He reported that the bandage was easy to remove, and that doing so was not painful; furthermore, he did not have problems with the bandage or healing and did not experience any medical changes. He found the bandage to be comfortable. The patient stated that the hanging feet of the prototype #1 bandage were not bothersome and were sturdy for the time that the bandage was on.

Prototype #2—We prepared a bandage using surgical packing as the tab (Figure 3). The packing was slowly placed around the site, which was already covered with nonadhesive gauze and fenestrated surgical gauze, with adequate spacing between each loop (for a total of 3 loops), 1 of which crossed over the third loop so that the adhesive bandaging tape could be removed easily. This allowed for a single tab that could be removed by a single pull. A final layer of adhesive tape was applied to ensure adequate pressure, similar to prototype #1. The same postoperative protocol was employed to provide a consistent standard of care. We recommend use of this prototype when surgical tape is not available, and surgical packing can be used as a substitute.

Practice Implications

Patients have a better appreciation for avoiding excess visits to medical offices due to the COVID-19 pandemic. The risk for exposure to SARS-CoV-2 infection is greater when patients who lack a support system must return to the office for aftercare or to have a bandage removed. Although protection offered by the COVID-19 vaccine alleviates concern, many patients have realized the benefits of only visiting medical offices in person when necessary.

The concept of pull tab bandages that can be removed by the patient at home has other applications. For example, patients who travel a long distance to see their physician will benefit from easier aftercare and avoid additional follow-up visits when provided with a self-removable bandage.

Practice Gap

A male patient presented with 2 concerning lesions, which histopathology revealed were invasive squamous cell carcinoma (SCC) on the right medial chest and SCC in situ on the right upper scapular region. Both were treated with wide local excision; margins were clear in our office the same day.

This case highlighted a practice gap in postoperative care. Two factors posed a challenge to proper postoperative wound care for our patient:

• Because of the high risk of transmission of SARS-CoV-2, the patient hoped to limit exposure by avoiding an office visit to remove the bandage.

• The patient did not have someone at home to serve as an immediate support system, which made it impossible for him to rely on others for postoperative wound care.

Previously, the patient had to ask a friend to remove a bandage for melanoma in situ on the inner aspect of the left upper arm. Therefore, after this procedure, the patient asked if the bandage could be fashioned in a manner that would allow him to remove it without assistance (Figure 1).

Technique

In constructing a bandage that is easier to remove, some necessary pressure that is provided by the bandage often is sacrificed by making it looser. Considering that our patient had moderate bleeding during the procedure—in part because he took low-dose aspirin (81 mg/d)—it was important to maintain firm pressure under the bandage postoperatively to help prevent untoward bleeding. Furthermore, because of the location of the treated site and the patient’s limited range of motion, it was not feasible for him to reach the area on the scapula and remove the bandage.¹

For easy self-removal, we designed a bandage with a pull tab that was within the patient’s reach. Suitable materials for the pull tab bandage included surgical tape, bandaging tape with adequate stretch, sterile nonadhesive gauze, fenestrated surgical gauze, and a topical emollient such as petroleum jelly or antibacterial ointment.

To clean the site and decrease the amount of oil that would reduce the effectiveness of the adhesive, the wound was prepared with 70% alcohol. The site was then treated with petroleum jelly.

Next, we designed 2 pull tab bandage prototypes that allowed easy self-removal. For both prototypes, sterile nonadhesive gauze was applied to the wound along with folded and fenestrated gauze, which provided pressure. We used prototype #1 in our patient, and prototype #2 was demonstrated as an option.

Prototype #1—We created 2 tabs—each 2-feet long—using bandaging tape that was folded on itself once horizontally (Figure 2). The tabs were aligned on either side of the wound, the tops of which sat approximately 2 inches above the top of the first layer of adhesive bandage. An initial layer of adhesive surgical dressing was applied to cover the wound; 1 inch of the dressing was left exposed on the top of each tab. In addition, there were 2 “feet” running on the bottom.

The tops of the tabs were folded back over the adhesive tape, creating a type of “hook.” An additional final layer of adhesive tape was applied to ensure adequate pressure on the surgical site.

The patient was instructed to remove the bandage 2 days after the procedure. The outcome was qualified through a 3-day postoperative telephone call. The patient was asked about postoperative pain and his level of satisfaction with treatment. He was asked if he had any changes such as bleeding, swelling, signs of infection, or increased pain in the days after surgery or perceived postoperative complications, such as irritation. We asked the patient about the relative ease of removing the bandage and if removal was painful. He reported that the bandage was easy to remove, and that doing so was not painful; furthermore, he did not have problems with the bandage or healing and did not experience any medical changes. He found the bandage to be comfortable. The patient stated that the hanging feet of the prototype #1 bandage were not bothersome and were sturdy for the time that the bandage was on.

Prototype #2—We prepared a bandage using surgical packing as the tab (Figure 3). The packing was slowly placed around the site, which was already covered with nonadhesive gauze and fenestrated surgical gauze, with adequate spacing between each loop (for a total of 3 loops), 1 of which crossed over the third loop so that the adhesive bandaging tape could be removed easily. This allowed for a single tab that could be removed by a single pull. A final layer of adhesive tape was applied to ensure adequate pressure, similar to prototype #1. The same postoperative protocol was employed to provide a consistent standard of care. We recommend use of this prototype when surgical tape is not available, and surgical packing can be used as a substitute.

Practice Implications

Patients have a better appreciation for avoiding excess visits to medical offices due to the COVID-19 pandemic. The risk for exposure to SARS-CoV-2 infection is greater when patients who lack a support system must return to the office for aftercare or to have a bandage removed. Although protection offered by the COVID-19 vaccine alleviates concern, many patients have realized the benefits of only visiting medical offices in person when necessary.

The concept of pull tab bandages that can be removed by the patient at home has other applications. For example, patients who travel a long distance to see their physician will benefit from easier aftercare and avoid additional follow-up visits when provided with a self-removable bandage.

Practice Gap

A male patient presented with 2 concerning lesions, which histopathology revealed were invasive squamous cell carcinoma (SCC) on the right medial chest and SCC in situ on the right upper scapular region. Both were treated with wide local excision; margins were clear in our office the same day.

This case highlighted a practice gap in postoperative care. Two factors posed a challenge to proper postoperative wound care for our patient:

• Because of the high risk of transmission of SARS-CoV-2, the patient hoped to limit exposure by avoiding an office visit to remove the bandage.

• The patient did not have someone at home to serve as an immediate support system, which made it impossible for him to rely on others for postoperative wound care.

Previously, the patient had to ask a friend to remove a bandage for melanoma in situ on the inner aspect of the left upper arm. Therefore, after this procedure, the patient asked if the bandage could be fashioned in a manner that would allow him to remove it without assistance (Figure 1).

Technique

In constructing a bandage that is easier to remove, some necessary pressure that is provided by the bandage often is sacrificed by making it looser. Considering that our patient had moderate bleeding during the procedure—in part because he took low-dose aspirin (81 mg/d)—it was important to maintain firm pressure under the bandage postoperatively to help prevent untoward bleeding. Furthermore, because of the location of the treated site and the patient’s limited range of motion, it was not feasible for him to reach the area on the scapula and remove the bandage.¹

For easy self-removal, we designed a bandage with a pull tab that was within the patient’s reach. Suitable materials for the pull tab bandage included surgical tape, bandaging tape with adequate stretch, sterile nonadhesive gauze, fenestrated surgical gauze, and a topical emollient such as petroleum jelly or antibacterial ointment.

To clean the site and decrease the amount of oil that would reduce the effectiveness of the adhesive, the wound was prepared with 70% alcohol. The site was then treated with petroleum jelly.

Next, we designed 2 pull tab bandage prototypes that allowed easy self-removal. For both prototypes, sterile nonadhesive gauze was applied to the wound along with folded and fenestrated gauze, which provided pressure. We used prototype #1 in our patient, and prototype #2 was demonstrated as an option.

Prototype #1—We created 2 tabs—each 2-feet long—using bandaging tape that was folded on itself once horizontally (Figure 2). The tabs were aligned on either side of the wound, the tops of which sat approximately 2 inches above the top of the first layer of adhesive bandage. An initial layer of adhesive surgical dressing was applied to cover the wound; 1 inch of the dressing was left exposed on the top of each tab. In addition, there were 2 “feet” running on the bottom.

The tops of the tabs were folded back over the adhesive tape, creating a type of “hook.” An additional final layer of adhesive tape was applied to ensure adequate pressure on the surgical site.

The patient was instructed to remove the bandage 2 days after the procedure. The outcome was qualified through a 3-day postoperative telephone call. The patient was asked about postoperative pain and his level of satisfaction with treatment. He was asked if he had any changes such as bleeding, swelling, signs of infection, or increased pain in the days after surgery or perceived postoperative complications, such as irritation. We asked the patient about the relative ease of removing the bandage and if removal was painful. He reported that the bandage was easy to remove, and that doing so was not painful; furthermore, he did not have problems with the bandage or healing and did not experience any medical changes. He found the bandage to be comfortable. The patient stated that the hanging feet of the prototype #1 bandage were not bothersome and were sturdy for the time that the bandage was on.

Prototype #2—We prepared a bandage using surgical packing as the tab (Figure 3). The packing was slowly placed around the site, which was already covered with nonadhesive gauze and fenestrated surgical gauze, with adequate spacing between each loop (for a total of 3 loops), 1 of which crossed over the third loop so that the adhesive bandaging tape could be removed easily. This allowed for a single tab that could be removed by a single pull. A final layer of adhesive tape was applied to ensure adequate pressure, similar to prototype #1. The same postoperative protocol was employed to provide a consistent standard of care. We recommend use of this prototype when surgical tape is not available, and surgical packing can be used as a substitute.

Practice Implications

Patients have a better appreciation for avoiding excess visits to medical offices due to the COVID-19 pandemic. The risk for exposure to SARS-CoV-2 infection is greater when patients who lack a support system must return to the office for aftercare or to have a bandage removed. Although protection offered by the COVID-19 vaccine alleviates concern, many patients have realized the benefits of only visiting medical offices in person when necessary.

The concept of pull tab bandages that can be removed by the patient at home has other applications. For example, patients who travel a long distance to see their physician will benefit from easier aftercare and avoid additional follow-up visits when provided with a self-removable bandage.

The Diagnosis: IgA Pemphigus

Histopathology revealed a neutrophilic pustule and vesicle formation underlying the corneal layer (Figure). Direct immunofluorescence (DIF) showed weak positive staining for IgA within the intercellular keratinocyte in the epithelial compartment and a negative pattern with IgG, IgM, C3, and fibrinogen. The patient received a 40-mg intralesional triamcinolone injection and was placed on an oral prednisone 50-mg taper within 5 days. The plaques, bullae, and pustules began to resolve, but the lesions returned 1 day later. Oral prednisone 10 mg daily was initiated for 1 month, which resulted in full resolution of the lesions.

IgA pemphigus is a rare autoimmune disorder characterized by the occurrence of painful pruritic blisters caused by circulating IgA antibodies, which react against keratinocyte cellular components responsible for mediating cell-to-cell adherence.¹ The etiology of IgA pemphigus presently remains elusive, though it has been reported to occur concomitantly with several chronic malignancies and inflammatory conditions. Although its etiology is unknown, IgA pemphigus most commonly is treated with oral dapsone and corticosteroids.²

IgA pemphigus can be divided into 2 primary subtypes: subcorneal pustular dermatosis and intraepidermal neutrophilic dermatosis.^1,3 The former is characterized by intercellular deposition of IgA that reacts to the glycoprotein desmocollin-1 in the upper layer of the epidermis. Intraepidermal neutrophilic dermatosis is distinguished by the presence of autoantibodies against the desmoglein members of the cadherin superfamily of proteins. Additionally, unlike subcorneal pustular dermatosis, intraepidermal neutrophilic dermatosis autoantibody reactivity occurs in the lower epidermis.⁴

The differential includes dermatitis herpetiformis, which is commonly seen on the elbows, knees, and buttocks, with DIF showing IgA deposition at the dermal papillae. Pemphigus foliaceus is distributed on the scalp, face, and trunk, with DIF showing IgG intercellular deposition. Pustular psoriasis presents as erythematous sterile pustules in a more localized annular pattern. Subcorneal pustular dermatosis (Sneddon-Wilkinson disease) has similar clinical and histological findings to IgA pemphigus; however, DIF is negative.

The Diagnosis: IgA Pemphigus

Histopathology revealed a neutrophilic pustule and vesicle formation underlying the corneal layer (Figure). Direct immunofluorescence (DIF) showed weak positive staining for IgA within the intercellular keratinocyte in the epithelial compartment and a negative pattern with IgG, IgM, C3, and fibrinogen. The patient received a 40-mg intralesional triamcinolone injection and was placed on an oral prednisone 50-mg taper within 5 days. The plaques, bullae, and pustules began to resolve, but the lesions returned 1 day later. Oral prednisone 10 mg daily was initiated for 1 month, which resulted in full resolution of the lesions.

IgA pemphigus is a rare autoimmune disorder characterized by the occurrence of painful pruritic blisters caused by circulating IgA antibodies, which react against keratinocyte cellular components responsible for mediating cell-to-cell adherence.¹ The etiology of IgA pemphigus presently remains elusive, though it has been reported to occur concomitantly with several chronic malignancies and inflammatory conditions. Although its etiology is unknown, IgA pemphigus most commonly is treated with oral dapsone and corticosteroids.²

IgA pemphigus can be divided into 2 primary subtypes: subcorneal pustular dermatosis and intraepidermal neutrophilic dermatosis.^1,3 The former is characterized by intercellular deposition of IgA that reacts to the glycoprotein desmocollin-1 in the upper layer of the epidermis. Intraepidermal neutrophilic dermatosis is distinguished by the presence of autoantibodies against the desmoglein members of the cadherin superfamily of proteins. Additionally, unlike subcorneal pustular dermatosis, intraepidermal neutrophilic dermatosis autoantibody reactivity occurs in the lower epidermis.⁴

The differential includes dermatitis herpetiformis, which is commonly seen on the elbows, knees, and buttocks, with DIF showing IgA deposition at the dermal papillae. Pemphigus foliaceus is distributed on the scalp, face, and trunk, with DIF showing IgG intercellular deposition. Pustular psoriasis presents as erythematous sterile pustules in a more localized annular pattern. Subcorneal pustular dermatosis (Sneddon-Wilkinson disease) has similar clinical and histological findings to IgA pemphigus; however, DIF is negative.

The Diagnosis: IgA Pemphigus

Histopathology revealed a neutrophilic pustule and vesicle formation underlying the corneal layer (Figure). Direct immunofluorescence (DIF) showed weak positive staining for IgA within the intercellular keratinocyte in the epithelial compartment and a negative pattern with IgG, IgM, C3, and fibrinogen. The patient received a 40-mg intralesional triamcinolone injection and was placed on an oral prednisone 50-mg taper within 5 days. The plaques, bullae, and pustules began to resolve, but the lesions returned 1 day later. Oral prednisone 10 mg daily was initiated for 1 month, which resulted in full resolution of the lesions.

IgA pemphigus is a rare autoimmune disorder characterized by the occurrence of painful pruritic blisters caused by circulating IgA antibodies, which react against keratinocyte cellular components responsible for mediating cell-to-cell adherence.¹ The etiology of IgA pemphigus presently remains elusive, though it has been reported to occur concomitantly with several chronic malignancies and inflammatory conditions. Although its etiology is unknown, IgA pemphigus most commonly is treated with oral dapsone and corticosteroids.²

IgA pemphigus can be divided into 2 primary subtypes: subcorneal pustular dermatosis and intraepidermal neutrophilic dermatosis.^1,3 The former is characterized by intercellular deposition of IgA that reacts to the glycoprotein desmocollin-1 in the upper layer of the epidermis. Intraepidermal neutrophilic dermatosis is distinguished by the presence of autoantibodies against the desmoglein members of the cadherin superfamily of proteins. Additionally, unlike subcorneal pustular dermatosis, intraepidermal neutrophilic dermatosis autoantibody reactivity occurs in the lower epidermis.⁴

The differential includes dermatitis herpetiformis, which is commonly seen on the elbows, knees, and buttocks, with DIF showing IgA deposition at the dermal papillae. Pemphigus foliaceus is distributed on the scalp, face, and trunk, with DIF showing IgG intercellular deposition. Pustular psoriasis presents as erythematous sterile pustules in a more localized annular pattern. Subcorneal pustular dermatosis (Sneddon-Wilkinson disease) has similar clinical and histological findings to IgA pemphigus; however, DIF is negative.

Perineuriomas are benign, slow-growing tumors derived from perineurial cells,¹ which form the structurally supportive perineurium that surrounds individual nerve fascicles.^2,3 Perineuriomas are classified into 2 main forms: intraneural or extraneural.⁴ Intraneural perineuriomas are found within the border of the peripheral nerve,⁵ while extraneural perineuriomas usually are found in soft tissue and skin. Extraneural perineuriomas can be further classified into variants based on their histologic appearance, including reticular, sclerosing, and plexiform subtypes. Extraneural perineuriomas usually present on the extremities or trunk of young to middle-aged adults as a well-circumscribed, painless, subcutaneous masses.¹ These tumors are especially unusual in children.⁴ We present 2 extraneural perineurioma cases in children, and we review the pertinent diagnostic features of perineurioma as well as the presentation in the pediatric population.

Case Reports

Patient 1—A 10-year-old boy with a history of cerebral palsy and related comorbidities presented to the clinic for evaluation of a lesion on the thigh with no associated pain, irritation, erythema, or drainage. Physical examination revealed a soft, pedunculated, mobile nodule on the right medial thigh. An elliptical excision was performed. Gross examination demonstrated a 2.0×2.0×1.8-cm polypoid nodule. Histologic examination showed a dermal-based proliferation of bland spindle cells (Figure 1). The cytomorphology was characterized by elongated tapering nuclei and many areas with delicate bipolar cytoplasmic processes. The constituent cells were arranged in a whorled pattern in a variably myxoid to collagenous stroma. The tumor cells were multifocally positive for CD34; focally positive for smooth muscle actin (SMA); and negative for S-100, epithelial membrane antigen (EMA), GLUT1, claudin-1, STAT6, and desmin. Rb protein was intact. The CD34 immunostain highlighted the cytoplasmic processes. Electron microscopy was performed because the immunohistochemical results were nonspecific despite the favorable histologic features for perineurioma and showed pinocytic vesicles with delicate cytoplasmic processes, characteristic of perineurioma (Figure 2). Follow-up visits were related to the management of multiple comorbidities; no known recurrence of the lesion was documented.

Patient 2—A 15-year-old adolescent boy with no notable medical history presented to the pediatric clinic for a bump on the right upper arm of 4 to 5 months’ duration. He did not recall an injury to the area and denied change in size, redness, bruising, or pain of the lesion. Ultrasonography demonstrated a 2.6×2.3×1.3-cm hypoechoic and slightly heterogeneous, well-circumscribed, subcutaneous mass with internal vascularity. The patient was then referred to a pediatric surgeon. The clinical differential included a lipoma, lymphadenopathy, or sebaceous cyst. An excision was performed. Gross inspection demonstrated a 7-g, 2.8×2.6×1.8-cm, homogeneous, tan-pink, rubbery nodule with minimal surrounding soft tissue. Histologic examination showed a bland proliferation of spindle cells with storiform and whorled patterns (Figure 3). No notable nuclear atypia or necrosis was identified. The tumor cells were focally positive for EMA (Figure 4), claudin-1, and CD34 and negative for S-100, SOX10, GLUT1, desmin, STAT6, pankeratin AE1/AE3, and SMA. The diagnosis of perineurioma was rendered. No recurrence of the lesion was appreciated clinically on a 6-month follow-up examination.

Comment

Characteristics of Perineuriomas—On gross evaluation, perineuriomas are firm, gray-white, and well circumscribed but not encapsulated. Histologically, perineuriomas can have a storiform, whorled, or lamellar pattern of spindle cells. Perivascular whorls can be a histologic clue. The spindle cells are bland appearing and typically are elongated and slender but can appear slightly ovoid and plump. The background stroma can be myxoid, collagenous, or mixed. There usually is no atypia, and mitotic figures are rare.^2,3,6,7 Intraneural perineuriomas vary architecturally in that they display a unique onion bulb–like appearance in which whorls of cytoplasmic material of variable sizes surround central axons.³

Diagnosis—The diagnosis of perineuriomas usually requires characteristic immunohistochemical and sometimes ultrastructural features. Perineuriomas are positive for EMA and GLUT1 and variable for CD34.⁶ Approximately 20% to 91% will be positive for claudin-1, a tight junction protein associated with perineuriomas.⁸ Of note, EMA and GLUT1 usually are positive in both neoplastic and nonneoplastic perineurial cells.^9,10 Occasionally, these tumors can be focally positive for SMA and negative for S-100 and glial fibrillary acidic protein. The bipolar, thin, delicate, cytoplasmic processes with long-tapering nuclei may be easier to appreciate on electron microscopy than on conventional light microscopy. In addition, the cells contain pinocytotic vesicles and a discontinuous external lamina, which may be helpful for diagnosis.¹⁰

Genetics—Genetic alterations in perineurioma continue to be elucidated. Although many soft tissue perineuriomas possess deletion of chromosome 22q material, this is not a consistent finding and is not pathognomonic. Notably, the NF2 tumor suppressor gene is found on chromosome 22.¹¹ For the sclerosing variant of perineurioma, rearrangements or deletions of chromosome 10q have been described. A study of 14 soft tissue/extraneural perineuriomas using whole-exome sequencing and single nucleotide polymorphism array showed 6 cases of recurrent chromosome 22q deletions containing the NF2 locus and 4 cases with a previously unreported finding of chromosome 17q deletions containing the NF1 locus that were mutually exclusive events in all but 1 case.¹² Although perineuriomas can harbor NF1 or NF2 mutations, perineuriomas are not considered to be associated with neurofibromatosis type 1 or 2 (NF1 or NF2, respectively). Patients with NF1 or NF2 and perineurioma are exceedingly rare. One pediatric patient with both soft tissue perineurioma and NF1 has been reported in the literature.¹³

Differential Diagnosis—Perineuriomas should be distinguished from other benign neural neoplasms of the skin and soft tissue. Commonly considered in the differential diagnosis is schwannoma and neurofibroma. Schwannomas are encapsulated epineurial nerve sheath tumors comprised of a neoplastic proliferation of Schwann cells. Schwannomas morphologically differ from perineuriomas because of the presence of the hypercellular Antoni A with Verocay bodies and the hypocellular myxoid Antoni B patterns of spindle cells with elongated wavy nuclei and tapered ends. Other features include hyalinized vessels, hemosiderin deposition, cystic degeneration, and/or degenerative atypia.^3,14 Importantly, the constituent cells of schwannomas are positive for S-100 and SOX10 and negative for EMA.³ Neurofibromas consist of fascicles and whorls of Schwann cells in a background myxoid stroma with scattered mast cells, lymphocytes, fibroblasts, and perineurial cells. Similar to schwannomas, neurofibromas also are positive for S-100 and negative for EMA.^3,14 Neurofibromas can have either a somatic or germline mutation of the biallelic NF1 gene on chromosome 17q11.2 with subsequent loss of protein neurofibromin activity.¹⁵ Less common but still a consideration are the hybrid peripheral nerve sheath tumors that may present with a biphasic or intermingled morphology. Combinations include neurofibroma-schwannoma, schwannoma-perineurioma, and neurofibroma-perineurioma. The hybrid schwannoma-perineurioma has a mixture of thin and plump spindle cells with tapered nuclei as well as patchy S-100 positivity corresponding to schwannian areas. Similarly, S-100 will highlight the wavy Schwann cells in neurofibroma-perineurioma as well as CD34-highlighting fibroblasts.^7,15 In both aforementioned hybrid tumors, EMA will be positive in the perineurial areas. Another potential diagnostic consideration that can occur in both pediatric and adult populations is dermatofibrosarcoma protuberans (DFSP), which is comprised of a dermal proliferation of monomorphic fusiform spindle cells. Although both perineuriomas and DFSP can have a storiform architecture, DFSP is more asymmetric and infiltrative. Dermatofibrosarcoma protuberans is recognized in areas of individual adipocyte trapping, referred to as honeycombing. Dermatofibrosarcoma protuberans typically does not express EMA, though the sclerosing variant of DFSP has been reported to sometimes demonstrate focal EMA reactivity.^11,14,16 For morphologically challenging cases, cytogenetic studies will show t(17;22) translocation fusing the COL1A1 and PDGFRB genes.¹⁶ Finally, for subcutaneous or deep-seated tumors, one also may consider other mesenchymal neoplasms, including solitary fibrous tumor, low-grade fibromyxoid sarcoma, or low-grade malignant peripheral nerve sheath tumor (MPNST).¹¹

Management—Perineuriomas are considered benign. The presence of mitotic figures, pleomorphism, and degenerative nuclear atypia akin to ancient change, as seen in ancient schwannoma, does not affect their benign clinical behavior. Treatment of a perineurioma typically is surgical excision with conservative margins and minimal chance of recurrence.^1,11 So-called malignant perineuriomas are better classified as MPNSTs with perineural differentiation or perineurial MPNST. They also are positive for EMA and may be distinguished from perineurioma by the presence of major atypia and an infiltrative growth pattern.^17,18

Considerations in the Pediatric Population—Few pediatric soft tissue perineuriomas have been reported. A clinicopathologic analysis by Hornick and Fletcher¹ of patients with soft tissue perineurioma showed that only 6 of 81 patients were younger than 20 years. The youngest reported case of perineurioma occurred as an extraneural perineurioma on the scalp in an infant.¹⁹ Only 1 soft tissue perineural MPNST has been reported in the pediatric population, arising on the face of an 11-year-old boy. In a case series of 11 pediatric perineuriomas, including extraneural and intraneural, there was no evidence of recurrence or metastasis at follow-up.⁴

Conclusion

Perineuriomas are rare benign peripheral nerve sheath tumors with unique histologic and immunohistochemical features. Soft tissue perineuriomas in the pediatric population are an important diagnostic consideration, especially for the pediatrician or dermatologist when encountering a well-circumscribed nodular soft tissue lesion of the extremity or when encountering a neural-appearing tumor in the subcutaneous tissue.

Acknowledgment—We would like to thank Christopher Fletcher, MD (Boston, Massachusetts), for his expertise in outside consultation for patient 1.

Perineuriomas are benign, slow-growing tumors derived from perineurial cells,¹ which form the structurally supportive perineurium that surrounds individual nerve fascicles.^2,3 Perineuriomas are classified into 2 main forms: intraneural or extraneural.⁴ Intraneural perineuriomas are found within the border of the peripheral nerve,⁵ while extraneural perineuriomas usually are found in soft tissue and skin. Extraneural perineuriomas can be further classified into variants based on their histologic appearance, including reticular, sclerosing, and plexiform subtypes. Extraneural perineuriomas usually present on the extremities or trunk of young to middle-aged adults as a well-circumscribed, painless, subcutaneous masses.¹ These tumors are especially unusual in children.⁴ We present 2 extraneural perineurioma cases in children, and we review the pertinent diagnostic features of perineurioma as well as the presentation in the pediatric population.

Case Reports

Patient 1—A 10-year-old boy with a history of cerebral palsy and related comorbidities presented to the clinic for evaluation of a lesion on the thigh with no associated pain, irritation, erythema, or drainage. Physical examination revealed a soft, pedunculated, mobile nodule on the right medial thigh. An elliptical excision was performed. Gross examination demonstrated a 2.0×2.0×1.8-cm polypoid nodule. Histologic examination showed a dermal-based proliferation of bland spindle cells (Figure 1). The cytomorphology was characterized by elongated tapering nuclei and many areas with delicate bipolar cytoplasmic processes. The constituent cells were arranged in a whorled pattern in a variably myxoid to collagenous stroma. The tumor cells were multifocally positive for CD34; focally positive for smooth muscle actin (SMA); and negative for S-100, epithelial membrane antigen (EMA), GLUT1, claudin-1, STAT6, and desmin. Rb protein was intact. The CD34 immunostain highlighted the cytoplasmic processes. Electron microscopy was performed because the immunohistochemical results were nonspecific despite the favorable histologic features for perineurioma and showed pinocytic vesicles with delicate cytoplasmic processes, characteristic of perineurioma (Figure 2). Follow-up visits were related to the management of multiple comorbidities; no known recurrence of the lesion was documented.

Patient 2—A 15-year-old adolescent boy with no notable medical history presented to the pediatric clinic for a bump on the right upper arm of 4 to 5 months’ duration. He did not recall an injury to the area and denied change in size, redness, bruising, or pain of the lesion. Ultrasonography demonstrated a 2.6×2.3×1.3-cm hypoechoic and slightly heterogeneous, well-circumscribed, subcutaneous mass with internal vascularity. The patient was then referred to a pediatric surgeon. The clinical differential included a lipoma, lymphadenopathy, or sebaceous cyst. An excision was performed. Gross inspection demonstrated a 7-g, 2.8×2.6×1.8-cm, homogeneous, tan-pink, rubbery nodule with minimal surrounding soft tissue. Histologic examination showed a bland proliferation of spindle cells with storiform and whorled patterns (Figure 3). No notable nuclear atypia or necrosis was identified. The tumor cells were focally positive for EMA (Figure 4), claudin-1, and CD34 and negative for S-100, SOX10, GLUT1, desmin, STAT6, pankeratin AE1/AE3, and SMA. The diagnosis of perineurioma was rendered. No recurrence of the lesion was appreciated clinically on a 6-month follow-up examination.

Comment

Characteristics of Perineuriomas—On gross evaluation, perineuriomas are firm, gray-white, and well circumscribed but not encapsulated. Histologically, perineuriomas can have a storiform, whorled, or lamellar pattern of spindle cells. Perivascular whorls can be a histologic clue. The spindle cells are bland appearing and typically are elongated and slender but can appear slightly ovoid and plump. The background stroma can be myxoid, collagenous, or mixed. There usually is no atypia, and mitotic figures are rare.^2,3,6,7 Intraneural perineuriomas vary architecturally in that they display a unique onion bulb–like appearance in which whorls of cytoplasmic material of variable sizes surround central axons.³

Diagnosis—The diagnosis of perineuriomas usually requires characteristic immunohistochemical and sometimes ultrastructural features. Perineuriomas are positive for EMA and GLUT1 and variable for CD34.⁶ Approximately 20% to 91% will be positive for claudin-1, a tight junction protein associated with perineuriomas.⁸ Of note, EMA and GLUT1 usually are positive in both neoplastic and nonneoplastic perineurial cells.^9,10 Occasionally, these tumors can be focally positive for SMA and negative for S-100 and glial fibrillary acidic protein. The bipolar, thin, delicate, cytoplasmic processes with long-tapering nuclei may be easier to appreciate on electron microscopy than on conventional light microscopy. In addition, the cells contain pinocytotic vesicles and a discontinuous external lamina, which may be helpful for diagnosis.¹⁰

Genetics—Genetic alterations in perineurioma continue to be elucidated. Although many soft tissue perineuriomas possess deletion of chromosome 22q material, this is not a consistent finding and is not pathognomonic. Notably, the NF2 tumor suppressor gene is found on chromosome 22.¹¹ For the sclerosing variant of perineurioma, rearrangements or deletions of chromosome 10q have been described. A study of 14 soft tissue/extraneural perineuriomas using whole-exome sequencing and single nucleotide polymorphism array showed 6 cases of recurrent chromosome 22q deletions containing the NF2 locus and 4 cases with a previously unreported finding of chromosome 17q deletions containing the NF1 locus that were mutually exclusive events in all but 1 case.¹² Although perineuriomas can harbor NF1 or NF2 mutations, perineuriomas are not considered to be associated with neurofibromatosis type 1 or 2 (NF1 or NF2, respectively). Patients with NF1 or NF2 and perineurioma are exceedingly rare. One pediatric patient with both soft tissue perineurioma and NF1 has been reported in the literature.¹³

Differential Diagnosis—Perineuriomas should be distinguished from other benign neural neoplasms of the skin and soft tissue. Commonly considered in the differential diagnosis is schwannoma and neurofibroma. Schwannomas are encapsulated epineurial nerve sheath tumors comprised of a neoplastic proliferation of Schwann cells. Schwannomas morphologically differ from perineuriomas because of the presence of the hypercellular Antoni A with Verocay bodies and the hypocellular myxoid Antoni B patterns of spindle cells with elongated wavy nuclei and tapered ends. Other features include hyalinized vessels, hemosiderin deposition, cystic degeneration, and/or degenerative atypia.^3,14 Importantly, the constituent cells of schwannomas are positive for S-100 and SOX10 and negative for EMA.³ Neurofibromas consist of fascicles and whorls of Schwann cells in a background myxoid stroma with scattered mast cells, lymphocytes, fibroblasts, and perineurial cells. Similar to schwannomas, neurofibromas also are positive for S-100 and negative for EMA.^3,14 Neurofibromas can have either a somatic or germline mutation of the biallelic NF1 gene on chromosome 17q11.2 with subsequent loss of protein neurofibromin activity.¹⁵ Less common but still a consideration are the hybrid peripheral nerve sheath tumors that may present with a biphasic or intermingled morphology. Combinations include neurofibroma-schwannoma, schwannoma-perineurioma, and neurofibroma-perineurioma. The hybrid schwannoma-perineurioma has a mixture of thin and plump spindle cells with tapered nuclei as well as patchy S-100 positivity corresponding to schwannian areas. Similarly, S-100 will highlight the wavy Schwann cells in neurofibroma-perineurioma as well as CD34-highlighting fibroblasts.^7,15 In both aforementioned hybrid tumors, EMA will be positive in the perineurial areas. Another potential diagnostic consideration that can occur in both pediatric and adult populations is dermatofibrosarcoma protuberans (DFSP), which is comprised of a dermal proliferation of monomorphic fusiform spindle cells. Although both perineuriomas and DFSP can have a storiform architecture, DFSP is more asymmetric and infiltrative. Dermatofibrosarcoma protuberans is recognized in areas of individual adipocyte trapping, referred to as honeycombing. Dermatofibrosarcoma protuberans typically does not express EMA, though the sclerosing variant of DFSP has been reported to sometimes demonstrate focal EMA reactivity.^11,14,16 For morphologically challenging cases, cytogenetic studies will show t(17;22) translocation fusing the COL1A1 and PDGFRB genes.¹⁶ Finally, for subcutaneous or deep-seated tumors, one also may consider other mesenchymal neoplasms, including solitary fibrous tumor, low-grade fibromyxoid sarcoma, or low-grade malignant peripheral nerve sheath tumor (MPNST).¹¹

Management—Perineuriomas are considered benign. The presence of mitotic figures, pleomorphism, and degenerative nuclear atypia akin to ancient change, as seen in ancient schwannoma, does not affect their benign clinical behavior. Treatment of a perineurioma typically is surgical excision with conservative margins and minimal chance of recurrence.^1,11 So-called malignant perineuriomas are better classified as MPNSTs with perineural differentiation or perineurial MPNST. They also are positive for EMA and may be distinguished from perineurioma by the presence of major atypia and an infiltrative growth pattern.^17,18

Considerations in the Pediatric Population—Few pediatric soft tissue perineuriomas have been reported. A clinicopathologic analysis by Hornick and Fletcher¹ of patients with soft tissue perineurioma showed that only 6 of 81 patients were younger than 20 years. The youngest reported case of perineurioma occurred as an extraneural perineurioma on the scalp in an infant.¹⁹ Only 1 soft tissue perineural MPNST has been reported in the pediatric population, arising on the face of an 11-year-old boy. In a case series of 11 pediatric perineuriomas, including extraneural and intraneural, there was no evidence of recurrence or metastasis at follow-up.⁴

Conclusion

Perineuriomas are rare benign peripheral nerve sheath tumors with unique histologic and immunohistochemical features. Soft tissue perineuriomas in the pediatric population are an important diagnostic consideration, especially for the pediatrician or dermatologist when encountering a well-circumscribed nodular soft tissue lesion of the extremity or when encountering a neural-appearing tumor in the subcutaneous tissue.

Acknowledgment—We would like to thank Christopher Fletcher, MD (Boston, Massachusetts), for his expertise in outside consultation for patient 1.

Perineuriomas are benign, slow-growing tumors derived from perineurial cells,¹ which form the structurally supportive perineurium that surrounds individual nerve fascicles.^2,3 Perineuriomas are classified into 2 main forms: intraneural or extraneural.⁴ Intraneural perineuriomas are found within the border of the peripheral nerve,⁵ while extraneural perineuriomas usually are found in soft tissue and skin. Extraneural perineuriomas can be further classified into variants based on their histologic appearance, including reticular, sclerosing, and plexiform subtypes. Extraneural perineuriomas usually present on the extremities or trunk of young to middle-aged adults as a well-circumscribed, painless, subcutaneous masses.¹ These tumors are especially unusual in children.⁴ We present 2 extraneural perineurioma cases in children, and we review the pertinent diagnostic features of perineurioma as well as the presentation in the pediatric population.

Case Reports

Patient 1—A 10-year-old boy with a history of cerebral palsy and related comorbidities presented to the clinic for evaluation of a lesion on the thigh with no associated pain, irritation, erythema, or drainage. Physical examination revealed a soft, pedunculated, mobile nodule on the right medial thigh. An elliptical excision was performed. Gross examination demonstrated a 2.0×2.0×1.8-cm polypoid nodule. Histologic examination showed a dermal-based proliferation of bland spindle cells (Figure 1). The cytomorphology was characterized by elongated tapering nuclei and many areas with delicate bipolar cytoplasmic processes. The constituent cells were arranged in a whorled pattern in a variably myxoid to collagenous stroma. The tumor cells were multifocally positive for CD34; focally positive for smooth muscle actin (SMA); and negative for S-100, epithelial membrane antigen (EMA), GLUT1, claudin-1, STAT6, and desmin. Rb protein was intact. The CD34 immunostain highlighted the cytoplasmic processes. Electron microscopy was performed because the immunohistochemical results were nonspecific despite the favorable histologic features for perineurioma and showed pinocytic vesicles with delicate cytoplasmic processes, characteristic of perineurioma (Figure 2). Follow-up visits were related to the management of multiple comorbidities; no known recurrence of the lesion was documented.

Patient 2—A 15-year-old adolescent boy with no notable medical history presented to the pediatric clinic for a bump on the right upper arm of 4 to 5 months’ duration. He did not recall an injury to the area and denied change in size, redness, bruising, or pain of the lesion. Ultrasonography demonstrated a 2.6×2.3×1.3-cm hypoechoic and slightly heterogeneous, well-circumscribed, subcutaneous mass with internal vascularity. The patient was then referred to a pediatric surgeon. The clinical differential included a lipoma, lymphadenopathy, or sebaceous cyst. An excision was performed. Gross inspection demonstrated a 7-g, 2.8×2.6×1.8-cm, homogeneous, tan-pink, rubbery nodule with minimal surrounding soft tissue. Histologic examination showed a bland proliferation of spindle cells with storiform and whorled patterns (Figure 3). No notable nuclear atypia or necrosis was identified. The tumor cells were focally positive for EMA (Figure 4), claudin-1, and CD34 and negative for S-100, SOX10, GLUT1, desmin, STAT6, pankeratin AE1/AE3, and SMA. The diagnosis of perineurioma was rendered. No recurrence of the lesion was appreciated clinically on a 6-month follow-up examination.

Comment

Characteristics of Perineuriomas—On gross evaluation, perineuriomas are firm, gray-white, and well circumscribed but not encapsulated. Histologically, perineuriomas can have a storiform, whorled, or lamellar pattern of spindle cells. Perivascular whorls can be a histologic clue. The spindle cells are bland appearing and typically are elongated and slender but can appear slightly ovoid and plump. The background stroma can be myxoid, collagenous, or mixed. There usually is no atypia, and mitotic figures are rare.^2,3,6,7 Intraneural perineuriomas vary architecturally in that they display a unique onion bulb–like appearance in which whorls of cytoplasmic material of variable sizes surround central axons.³

Diagnosis—The diagnosis of perineuriomas usually requires characteristic immunohistochemical and sometimes ultrastructural features. Perineuriomas are positive for EMA and GLUT1 and variable for CD34.⁶ Approximately 20% to 91% will be positive for claudin-1, a tight junction protein associated with perineuriomas.⁸ Of note, EMA and GLUT1 usually are positive in both neoplastic and nonneoplastic perineurial cells.^9,10 Occasionally, these tumors can be focally positive for SMA and negative for S-100 and glial fibrillary acidic protein. The bipolar, thin, delicate, cytoplasmic processes with long-tapering nuclei may be easier to appreciate on electron microscopy than on conventional light microscopy. In addition, the cells contain pinocytotic vesicles and a discontinuous external lamina, which may be helpful for diagnosis.¹⁰

Genetics—Genetic alterations in perineurioma continue to be elucidated. Although many soft tissue perineuriomas possess deletion of chromosome 22q material, this is not a consistent finding and is not pathognomonic. Notably, the NF2 tumor suppressor gene is found on chromosome 22.¹¹ For the sclerosing variant of perineurioma, rearrangements or deletions of chromosome 10q have been described. A study of 14 soft tissue/extraneural perineuriomas using whole-exome sequencing and single nucleotide polymorphism array showed 6 cases of recurrent chromosome 22q deletions containing the NF2 locus and 4 cases with a previously unreported finding of chromosome 17q deletions containing the NF1 locus that were mutually exclusive events in all but 1 case.¹² Although perineuriomas can harbor NF1 or NF2 mutations, perineuriomas are not considered to be associated with neurofibromatosis type 1 or 2 (NF1 or NF2, respectively). Patients with NF1 or NF2 and perineurioma are exceedingly rare. One pediatric patient with both soft tissue perineurioma and NF1 has been reported in the literature.¹³

Differential Diagnosis—Perineuriomas should be distinguished from other benign neural neoplasms of the skin and soft tissue. Commonly considered in the differential diagnosis is schwannoma and neurofibroma. Schwannomas are encapsulated epineurial nerve sheath tumors comprised of a neoplastic proliferation of Schwann cells. Schwannomas morphologically differ from perineuriomas because of the presence of the hypercellular Antoni A with Verocay bodies and the hypocellular myxoid Antoni B patterns of spindle cells with elongated wavy nuclei and tapered ends. Other features include hyalinized vessels, hemosiderin deposition, cystic degeneration, and/or degenerative atypia.^3,14 Importantly, the constituent cells of schwannomas are positive for S-100 and SOX10 and negative for EMA.³ Neurofibromas consist of fascicles and whorls of Schwann cells in a background myxoid stroma with scattered mast cells, lymphocytes, fibroblasts, and perineurial cells. Similar to schwannomas, neurofibromas also are positive for S-100 and negative for EMA.^3,14 Neurofibromas can have either a somatic or germline mutation of the biallelic NF1 gene on chromosome 17q11.2 with subsequent loss of protein neurofibromin activity.¹⁵ Less common but still a consideration are the hybrid peripheral nerve sheath tumors that may present with a biphasic or intermingled morphology. Combinations include neurofibroma-schwannoma, schwannoma-perineurioma, and neurofibroma-perineurioma. The hybrid schwannoma-perineurioma has a mixture of thin and plump spindle cells with tapered nuclei as well as patchy S-100 positivity corresponding to schwannian areas. Similarly, S-100 will highlight the wavy Schwann cells in neurofibroma-perineurioma as well as CD34-highlighting fibroblasts.^7,15 In both aforementioned hybrid tumors, EMA will be positive in the perineurial areas. Another potential diagnostic consideration that can occur in both pediatric and adult populations is dermatofibrosarcoma protuberans (DFSP), which is comprised of a dermal proliferation of monomorphic fusiform spindle cells. Although both perineuriomas and DFSP can have a storiform architecture, DFSP is more asymmetric and infiltrative. Dermatofibrosarcoma protuberans is recognized in areas of individual adipocyte trapping, referred to as honeycombing. Dermatofibrosarcoma protuberans typically does not express EMA, though the sclerosing variant of DFSP has been reported to sometimes demonstrate focal EMA reactivity.^11,14,16 For morphologically challenging cases, cytogenetic studies will show t(17;22) translocation fusing the COL1A1 and PDGFRB genes.¹⁶ Finally, for subcutaneous or deep-seated tumors, one also may consider other mesenchymal neoplasms, including solitary fibrous tumor, low-grade fibromyxoid sarcoma, or low-grade malignant peripheral nerve sheath tumor (MPNST).¹¹

Management—Perineuriomas are considered benign. The presence of mitotic figures, pleomorphism, and degenerative nuclear atypia akin to ancient change, as seen in ancient schwannoma, does not affect their benign clinical behavior. Treatment of a perineurioma typically is surgical excision with conservative margins and minimal chance of recurrence.^1,11 So-called malignant perineuriomas are better classified as MPNSTs with perineural differentiation or perineurial MPNST. They also are positive for EMA and may be distinguished from perineurioma by the presence of major atypia and an infiltrative growth pattern.^17,18

Considerations in the Pediatric Population—Few pediatric soft tissue perineuriomas have been reported. A clinicopathologic analysis by Hornick and Fletcher¹ of patients with soft tissue perineurioma showed that only 6 of 81 patients were younger than 20 years. The youngest reported case of perineurioma occurred as an extraneural perineurioma on the scalp in an infant.¹⁹ Only 1 soft tissue perineural MPNST has been reported in the pediatric population, arising on the face of an 11-year-old boy. In a case series of 11 pediatric perineuriomas, including extraneural and intraneural, there was no evidence of recurrence or metastasis at follow-up.⁴

Conclusion

Perineuriomas are rare benign peripheral nerve sheath tumors with unique histologic and immunohistochemical features. Soft tissue perineuriomas in the pediatric population are an important diagnostic consideration, especially for the pediatrician or dermatologist when encountering a well-circumscribed nodular soft tissue lesion of the extremity or when encountering a neural-appearing tumor in the subcutaneous tissue.

Acknowledgment—We would like to thank Christopher Fletcher, MD (Boston, Massachusetts), for his expertise in outside consultation for patient 1.

Atopic dermatitis (AD), or eczema, is a common inflammatory skin disease notorious for its chronic, relapsing, and often frustrating disease course. Although as many as 25% of children in the United States are affected by this condition and its impact on the quality of life of affected patients and families is profound,^1-3 therapeutic advances in the pediatric population have been fairly limited until recently.

Over the last 10 years, there has been robust investigation into pediatric AD therapeutics, with many topical and systemic medications either recently approved or under clinical investigation. These developments are changing the landscape of the management of pediatric AD and raise a set of fascinating questions about how early and aggressive intervention might change the course of this disease. We discuss current limitations in the field that may be addressed with additional research.

New Topical Medications

In the last several years, there has been a rapid increase in efforts to develop new topical agents to manage AD. Until the beginning of the 21st century, the dermatologist’s arsenal was limited to topical corticosteroids (TCs). In the early 2000s, attention shifted to topical calcineurin inhibitors as nonsteroidal alternatives when the US Food and Drug Administration (FDA) approved topical tacrolimus and pimecrolimus for AD. In 2016, crisaborole (a phosphodiesterase-4 [PDE4] inhibitor) was approved by the FDA for use in mild to moderate AD in patients 2 years and older, marking a new age of development for topical AD therapies. In 2021, the FDA approved ruxolitinib (a topical Janus kinase [JAK] 1/2 inhibitor) for use in mild to moderate AD in patients 12 years and older.

Roflumilast (ARQ-151) and difamilast (OPA-15406)(members of the PDE4 inhibitor class) are undergoing investigation for pediatric AD. A phase 3 clinical trial for roflumilast for AD is underway (ClinicalTrial.gov Identifier: NCT04845620); it is already approved for psoriasis in patients 12 years and older. A phase 3 trial of difamilast (NCT03911401) was recently completed, with results supporting the drug’s safety and efficacy in AD management.⁴ Efforts to synthesize new better-targeted PDE4 inhibitors are ongoing.⁵

Tapinarof (a novel aryl hydrocarbon receptor-modulating agent) is approved for psoriasis in adults, and a phase 3 trial for management of pediatric AD is underway (NCT05032859) after phase 2 trials revealed promising results.⁶

Lastly, the microbiome is a target for AD topical therapies. A recently completed phase 1 trial of bacteriotherapy with Staphylococcus hominis A9 transplant lotion showed promising results (NCT03151148).⁷ Although this bacteriotherapy technique is early in development and has been studied only in adult patients, results are exciting because they represent a gateway to a largely unexplored realm of potential future therapies.

Standard of Care—How will these new topical therapies impact our standard of care for pediatric AD patients? Topical corticosteroids are still a pillar of topical AD therapy, but the potential for nonsteroidal topical agents as alternatives and used in combination therapeutic regimens has expanded exponentially. It is uncertain how we might individualize regimens tailored to patient-specific factors because the standard approach has been to test drugs as monotherapy, with vehicle comparisons or with reference medications in Europe.

Newer topical nonsteroidal agents may offer several opportunities. First, they may help avoid local and systemic adverse effects that often limit the use of current standard therapy.⁸ This capability may prove essential in bridging TC treatments and serving as long-term maintenance therapies to decrease the frequency of eczema flares. Second, they can alleviate the need for different medication strengths for different body regions, thereby allowing for simplification of regimens and potentially increased adherence and decreased disease burden—a boon to affected patients and caregivers.

Although the efficacy and long-term safety profile of these new drugs require further study, it does not seem unreasonable to look forward to achieving levels of optimization and individualization with topical regimens for AD in the near future that makes flares in patients with mild to moderate AD a phenomenon of the past.

Advances in Systemic Therapy

Systemic therapeutics in pediatric AD also recently entered an exciting era of development. Traditional systemic agents, including cyclosporine, methotrexate, azathioprine, and mycophenolate mofetil, have existed for decades but have not been widely utilized for moderate to severe AD in the United States, especially in the pediatric population, likely because these drugs lacked FDA approval and they can cause a range of adverse effects, including notable immunosuppression.⁹

Introduction and approval of dupilumab in 2017 by the FDA was revolutionary in this field. As a monoclonal antibody targeted against IL-4 and IL-13, dupilumab has consistently demonstrated strong long-term efficacy for pediatric AD and has an acceptable safety profile in children and adolescents.^10-14 Expansion of the label to include children as young as 6 months with moderate to severe AD seems an important milestone in pediatric AD care.

Since the approval of dupilumab for adolescents and children aged 6 to 12 years, global experience has supported expanded use of systemic agents for patients who have an inadequate response to TCs and previously approved nonsteroidal topical agents. How expansive the use of systemics will be in younger children depends on how their long-term use impacts the disease course, whether therapy is disease modifying, and whether early use can curb the development of comorbidities.

Investigations into targeted systemic therapeutics for eczematous dermatitis are not limited to dupilumab. In a study of adolescents as young as 12 years, tralokinumab (an IL-13 pathway inhibitor) demonstrated an Eczema Area Severity Index-75 of 27.8% to 28.6% and a mean decrease in the SCORing Atopic Dermatitis index of 27.5 to 29.1, with minimal adverse effects.¹⁵ Lebrikizumab, another biologic IL-13 inhibitor with strong published safety and efficacy data in adults, has completed short- and longer-term studies in adolescents (NCT04178967 and NCT04146363).¹⁶ The drug received FDA Fast Track designation for moderate to severe AD in patients 12 years and older after showing positive data.¹⁷

This push to targeted therapy stretches beyond monoclonal antibodies. In the last few years, oral JAK inhibitors have emerged as a new class of systemic therapy for eczematous dermatitis. Upadacitinib, a JAK1 selective inhibitor, was approved by the FDA in 2022 for patients 12 years and older with AD and has data that supports its efficacy in adolescents and adults.¹⁸ Other JAK inhibitors including the selective JAK1 inhibitor abrocitinib and the combined JAK1/2 inhibitor baricitinib are being studied for pediatric AD (NCT04564755, NCT03422822, and NCT03952559), with most evidence to date supporting their safety and efficacy, at least over the short-term.¹⁹

The study of these and other advanced systemic therapies for eczematous dermatitis is transforming the toolbox for pediatric AD care. Although long-term data are lacking for some of these medications, it is possible that newer agents may decrease reliance on older immunosuppressants, such as systemic corticosteroids, cyclosporine, and methotrexate. Unanswered questions include: How and which systemic medications may alter the course of the disease? What is the disease modification for AD? What is the impact on comorbidities over time?

What’s Missing?

The field of pediatric AD has experienced exciting new developments with the emergence of targeted therapeutics, but those new agents require more long-term study, though we already have longer-term data on crisaborole and dupilumab.^10-14,20 Studies of the long-term use of these new treatments on comorbidities of pediatric AD—mental health outcomes, cardiovascular disease, effects on the family, and other allergic conditions—are needed.²¹ Furthermore, clinical guidelines that address indications, timing of use, tapering, and discontinuation of new treatments depend on long-term experience and data collection.

Therefore, it is prudent that investigators, companies, payers, patients, and families support phase 4, long-term extension, and registry studies, which will expand our knowledge of AD medications and their impact on the disease over time.

Final Thoughts

Medications to treat AD are reaching a new level of advancement—from topical agents that target novel pathways to revolutionary biologics and systemic medications. Although there are knowledge gaps on these new therapeutics, the standard of care is already rapidly changing as the expectations of clinicians, patients, and families advance with each addition to the provider’s toolbox.

Atopic dermatitis (AD), or eczema, is a common inflammatory skin disease notorious for its chronic, relapsing, and often frustrating disease course. Although as many as 25% of children in the United States are affected by this condition and its impact on the quality of life of affected patients and families is profound,^1-3 therapeutic advances in the pediatric population have been fairly limited until recently.

Over the last 10 years, there has been robust investigation into pediatric AD therapeutics, with many topical and systemic medications either recently approved or under clinical investigation. These developments are changing the landscape of the management of pediatric AD and raise a set of fascinating questions about how early and aggressive intervention might change the course of this disease. We discuss current limitations in the field that may be addressed with additional research.

New Topical Medications

In the last several years, there has been a rapid increase in efforts to develop new topical agents to manage AD. Until the beginning of the 21st century, the dermatologist’s arsenal was limited to topical corticosteroids (TCs). In the early 2000s, attention shifted to topical calcineurin inhibitors as nonsteroidal alternatives when the US Food and Drug Administration (FDA) approved topical tacrolimus and pimecrolimus for AD. In 2016, crisaborole (a phosphodiesterase-4 [PDE4] inhibitor) was approved by the FDA for use in mild to moderate AD in patients 2 years and older, marking a new age of development for topical AD therapies. In 2021, the FDA approved ruxolitinib (a topical Janus kinase [JAK] 1/2 inhibitor) for use in mild to moderate AD in patients 12 years and older.

Roflumilast (ARQ-151) and difamilast (OPA-15406)(members of the PDE4 inhibitor class) are undergoing investigation for pediatric AD. A phase 3 clinical trial for roflumilast for AD is underway (ClinicalTrial.gov Identifier: NCT04845620); it is already approved for psoriasis in patients 12 years and older. A phase 3 trial of difamilast (NCT03911401) was recently completed, with results supporting the drug’s safety and efficacy in AD management.⁴ Efforts to synthesize new better-targeted PDE4 inhibitors are ongoing.⁵

Tapinarof (a novel aryl hydrocarbon receptor-modulating agent) is approved for psoriasis in adults, and a phase 3 trial for management of pediatric AD is underway (NCT05032859) after phase 2 trials revealed promising results.⁶

Lastly, the microbiome is a target for AD topical therapies. A recently completed phase 1 trial of bacteriotherapy with Staphylococcus hominis A9 transplant lotion showed promising results (NCT03151148).⁷ Although this bacteriotherapy technique is early in development and has been studied only in adult patients, results are exciting because they represent a gateway to a largely unexplored realm of potential future therapies.

Standard of Care—How will these new topical therapies impact our standard of care for pediatric AD patients? Topical corticosteroids are still a pillar of topical AD therapy, but the potential for nonsteroidal topical agents as alternatives and used in combination therapeutic regimens has expanded exponentially. It is uncertain how we might individualize regimens tailored to patient-specific factors because the standard approach has been to test drugs as monotherapy, with vehicle comparisons or with reference medications in Europe.

Newer topical nonsteroidal agents may offer several opportunities. First, they may help avoid local and systemic adverse effects that often limit the use of current standard therapy.⁸ This capability may prove essential in bridging TC treatments and serving as long-term maintenance therapies to decrease the frequency of eczema flares. Second, they can alleviate the need for different medication strengths for different body regions, thereby allowing for simplification of regimens and potentially increased adherence and decreased disease burden—a boon to affected patients and caregivers.

Although the efficacy and long-term safety profile of these new drugs require further study, it does not seem unreasonable to look forward to achieving levels of optimization and individualization with topical regimens for AD in the near future that makes flares in patients with mild to moderate AD a phenomenon of the past.

Advances in Systemic Therapy

Systemic therapeutics in pediatric AD also recently entered an exciting era of development. Traditional systemic agents, including cyclosporine, methotrexate, azathioprine, and mycophenolate mofetil, have existed for decades but have not been widely utilized for moderate to severe AD in the United States, especially in the pediatric population, likely because these drugs lacked FDA approval and they can cause a range of adverse effects, including notable immunosuppression.⁹

Introduction and approval of dupilumab in 2017 by the FDA was revolutionary in this field. As a monoclonal antibody targeted against IL-4 and IL-13, dupilumab has consistently demonstrated strong long-term efficacy for pediatric AD and has an acceptable safety profile in children and adolescents.^10-14 Expansion of the label to include children as young as 6 months with moderate to severe AD seems an important milestone in pediatric AD care.

Since the approval of dupilumab for adolescents and children aged 6 to 12 years, global experience has supported expanded use of systemic agents for patients who have an inadequate response to TCs and previously approved nonsteroidal topical agents. How expansive the use of systemics will be in younger children depends on how their long-term use impacts the disease course, whether therapy is disease modifying, and whether early use can curb the development of comorbidities.

Investigations into targeted systemic therapeutics for eczematous dermatitis are not limited to dupilumab. In a study of adolescents as young as 12 years, tralokinumab (an IL-13 pathway inhibitor) demonstrated an Eczema Area Severity Index-75 of 27.8% to 28.6% and a mean decrease in the SCORing Atopic Dermatitis index of 27.5 to 29.1, with minimal adverse effects.¹⁵ Lebrikizumab, another biologic IL-13 inhibitor with strong published safety and efficacy data in adults, has completed short- and longer-term studies in adolescents (NCT04178967 and NCT04146363).¹⁶ The drug received FDA Fast Track designation for moderate to severe AD in patients 12 years and older after showing positive data.¹⁷

This push to targeted therapy stretches beyond monoclonal antibodies. In the last few years, oral JAK inhibitors have emerged as a new class of systemic therapy for eczematous dermatitis. Upadacitinib, a JAK1 selective inhibitor, was approved by the FDA in 2022 for patients 12 years and older with AD and has data that supports its efficacy in adolescents and adults.¹⁸ Other JAK inhibitors including the selective JAK1 inhibitor abrocitinib and the combined JAK1/2 inhibitor baricitinib are being studied for pediatric AD (NCT04564755, NCT03422822, and NCT03952559), with most evidence to date supporting their safety and efficacy, at least over the short-term.¹⁹

The study of these and other advanced systemic therapies for eczematous dermatitis is transforming the toolbox for pediatric AD care. Although long-term data are lacking for some of these medications, it is possible that newer agents may decrease reliance on older immunosuppressants, such as systemic corticosteroids, cyclosporine, and methotrexate. Unanswered questions include: How and which systemic medications may alter the course of the disease? What is the disease modification for AD? What is the impact on comorbidities over time?

What’s Missing?

The field of pediatric AD has experienced exciting new developments with the emergence of targeted therapeutics, but those new agents require more long-term study, though we already have longer-term data on crisaborole and dupilumab.^10-14,20 Studies of the long-term use of these new treatments on comorbidities of pediatric AD—mental health outcomes, cardiovascular disease, effects on the family, and other allergic conditions—are needed.²¹ Furthermore, clinical guidelines that address indications, timing of use, tapering, and discontinuation of new treatments depend on long-term experience and data collection.

Therefore, it is prudent that investigators, companies, payers, patients, and families support phase 4, long-term extension, and registry studies, which will expand our knowledge of AD medications and their impact on the disease over time.

Final Thoughts

Medications to treat AD are reaching a new level of advancement—from topical agents that target novel pathways to revolutionary biologics and systemic medications. Although there are knowledge gaps on these new therapeutics, the standard of care is already rapidly changing as the expectations of clinicians, patients, and families advance with each addition to the provider’s toolbox.

Atopic dermatitis (AD), or eczema, is a common inflammatory skin disease notorious for its chronic, relapsing, and often frustrating disease course. Although as many as 25% of children in the United States are affected by this condition and its impact on the quality of life of affected patients and families is profound,^1-3 therapeutic advances in the pediatric population have been fairly limited until recently.

Over the last 10 years, there has been robust investigation into pediatric AD therapeutics, with many topical and systemic medications either recently approved or under clinical investigation. These developments are changing the landscape of the management of pediatric AD and raise a set of fascinating questions about how early and aggressive intervention might change the course of this disease. We discuss current limitations in the field that may be addressed with additional research.

New Topical Medications

In the last several years, there has been a rapid increase in efforts to develop new topical agents to manage AD. Until the beginning of the 21st century, the dermatologist’s arsenal was limited to topical corticosteroids (TCs). In the early 2000s, attention shifted to topical calcineurin inhibitors as nonsteroidal alternatives when the US Food and Drug Administration (FDA) approved topical tacrolimus and pimecrolimus for AD. In 2016, crisaborole (a phosphodiesterase-4 [PDE4] inhibitor) was approved by the FDA for use in mild to moderate AD in patients 2 years and older, marking a new age of development for topical AD therapies. In 2021, the FDA approved ruxolitinib (a topical Janus kinase [JAK] 1/2 inhibitor) for use in mild to moderate AD in patients 12 years and older.

Roflumilast (ARQ-151) and difamilast (OPA-15406)(members of the PDE4 inhibitor class) are undergoing investigation for pediatric AD. A phase 3 clinical trial for roflumilast for AD is underway (ClinicalTrial.gov Identifier: NCT04845620); it is already approved for psoriasis in patients 12 years and older. A phase 3 trial of difamilast (NCT03911401) was recently completed, with results supporting the drug’s safety and efficacy in AD management.⁴ Efforts to synthesize new better-targeted PDE4 inhibitors are ongoing.⁵

Tapinarof (a novel aryl hydrocarbon receptor-modulating agent) is approved for psoriasis in adults, and a phase 3 trial for management of pediatric AD is underway (NCT05032859) after phase 2 trials revealed promising results.⁶

Lastly, the microbiome is a target for AD topical therapies. A recently completed phase 1 trial of bacteriotherapy with Staphylococcus hominis A9 transplant lotion showed promising results (NCT03151148).⁷ Although this bacteriotherapy technique is early in development and has been studied only in adult patients, results are exciting because they represent a gateway to a largely unexplored realm of potential future therapies.

Standard of Care—How will these new topical therapies impact our standard of care for pediatric AD patients? Topical corticosteroids are still a pillar of topical AD therapy, but the potential for nonsteroidal topical agents as alternatives and used in combination therapeutic regimens has expanded exponentially. It is uncertain how we might individualize regimens tailored to patient-specific factors because the standard approach has been to test drugs as monotherapy, with vehicle comparisons or with reference medications in Europe.

Newer topical nonsteroidal agents may offer several opportunities. First, they may help avoid local and systemic adverse effects that often limit the use of current standard therapy.⁸ This capability may prove essential in bridging TC treatments and serving as long-term maintenance therapies to decrease the frequency of eczema flares. Second, they can alleviate the need for different medication strengths for different body regions, thereby allowing for simplification of regimens and potentially increased adherence and decreased disease burden—a boon to affected patients and caregivers.

Although the efficacy and long-term safety profile of these new drugs require further study, it does not seem unreasonable to look forward to achieving levels of optimization and individualization with topical regimens for AD in the near future that makes flares in patients with mild to moderate AD a phenomenon of the past.

Advances in Systemic Therapy

Systemic therapeutics in pediatric AD also recently entered an exciting era of development. Traditional systemic agents, including cyclosporine, methotrexate, azathioprine, and mycophenolate mofetil, have existed for decades but have not been widely utilized for moderate to severe AD in the United States, especially in the pediatric population, likely because these drugs lacked FDA approval and they can cause a range of adverse effects, including notable immunosuppression.⁹

Introduction and approval of dupilumab in 2017 by the FDA was revolutionary in this field. As a monoclonal antibody targeted against IL-4 and IL-13, dupilumab has consistently demonstrated strong long-term efficacy for pediatric AD and has an acceptable safety profile in children and adolescents.^10-14 Expansion of the label to include children as young as 6 months with moderate to severe AD seems an important milestone in pediatric AD care.

Since the approval of dupilumab for adolescents and children aged 6 to 12 years, global experience has supported expanded use of systemic agents for patients who have an inadequate response to TCs and previously approved nonsteroidal topical agents. How expansive the use of systemics will be in younger children depends on how their long-term use impacts the disease course, whether therapy is disease modifying, and whether early use can curb the development of comorbidities.

Investigations into targeted systemic therapeutics for eczematous dermatitis are not limited to dupilumab. In a study of adolescents as young as 12 years, tralokinumab (an IL-13 pathway inhibitor) demonstrated an Eczema Area Severity Index-75 of 27.8% to 28.6% and a mean decrease in the SCORing Atopic Dermatitis index of 27.5 to 29.1, with minimal adverse effects.¹⁵ Lebrikizumab, another biologic IL-13 inhibitor with strong published safety and efficacy data in adults, has completed short- and longer-term studies in adolescents (NCT04178967 and NCT04146363).¹⁶ The drug received FDA Fast Track designation for moderate to severe AD in patients 12 years and older after showing positive data.¹⁷

This push to targeted therapy stretches beyond monoclonal antibodies. In the last few years, oral JAK inhibitors have emerged as a new class of systemic therapy for eczematous dermatitis. Upadacitinib, a JAK1 selective inhibitor, was approved by the FDA in 2022 for patients 12 years and older with AD and has data that supports its efficacy in adolescents and adults.¹⁸ Other JAK inhibitors including the selective JAK1 inhibitor abrocitinib and the combined JAK1/2 inhibitor baricitinib are being studied for pediatric AD (NCT04564755, NCT03422822, and NCT03952559), with most evidence to date supporting their safety and efficacy, at least over the short-term.¹⁹

The study of these and other advanced systemic therapies for eczematous dermatitis is transforming the toolbox for pediatric AD care. Although long-term data are lacking for some of these medications, it is possible that newer agents may decrease reliance on older immunosuppressants, such as systemic corticosteroids, cyclosporine, and methotrexate. Unanswered questions include: How and which systemic medications may alter the course of the disease? What is the disease modification for AD? What is the impact on comorbidities over time?

What’s Missing?

The field of pediatric AD has experienced exciting new developments with the emergence of targeted therapeutics, but those new agents require more long-term study, though we already have longer-term data on crisaborole and dupilumab.^10-14,20 Studies of the long-term use of these new treatments on comorbidities of pediatric AD—mental health outcomes, cardiovascular disease, effects on the family, and other allergic conditions—are needed.²¹ Furthermore, clinical guidelines that address indications, timing of use, tapering, and discontinuation of new treatments depend on long-term experience and data collection.

Therefore, it is prudent that investigators, companies, payers, patients, and families support phase 4, long-term extension, and registry studies, which will expand our knowledge of AD medications and their impact on the disease over time.

Final Thoughts

Medications to treat AD are reaching a new level of advancement—from topical agents that target novel pathways to revolutionary biologics and systemic medications. Although there are knowledge gaps on these new therapeutics, the standard of care is already rapidly changing as the expectations of clinicians, patients, and families advance with each addition to the provider’s toolbox.