In a case report by Najarian,6 a morbilliform exanthem was seen on the legs, arms, and trunk of a patient who was otherwise asymptomatic but tested positive for COVID-19. The morbilliform exanthem then became confluent on the trunk. Notably, the patient reported pain of the hands and feet.6
Another case report described a patient with edematous annular plaques on the palms, neck, and upper extremities who presented solely with fever.7 The biopsy specimen was nonspecific but indicated a viral exanthem. Histopathology showed perivascular lymphocytic infiltrate, dermal edema and vacuoles, spongiosis, dyskeratotic basilar keratinocytes, and few neutrophils without eosinophils.7
A confluent eczematous eruption in the flexural areas, the antecubital fossae, and axillary folds has been found in COVID-19 patients.21,22 An elderly patient with severe COVID-19 developed a squamous erythematous periumbilical patch 1 day after hospital admission. The cutaneous eruption rapidly progressed to digitate scaly plaques on the trunk, thighs, and flank. A biopsy specimen showed epidermal spongiosis, vesicles containing lymphocytes, and Langerhans cells. The upper dermis demonstrated a lymphohistiocytic infiltrate.23
Pityriasis Rosea–Like Eruption
In Iran, a COVID-19–infected patient developed an erythematous papulosquamous eruption with a herald patch and trailing scales 3 days after viral symptoms, resembling that of pityriasis rosea.24 Nests of Langerhans cells within the epidermis are seen in many viral exanthems, including cases of COVID-19 and pityriasis rosea.25
According to a number of case reports, urticarial lesions have been the first presenting sign of COVID-19 infection, most resolving with antihistamines.10,11 Some patients with more severe symptoms have had widespread urticaria. An urticarial exanthem appearing on the bilateral thighs and buttocks may be the initial sign of infection.12,15 Pruritic erythematous plaques over the face and acral areas is another initial sign. Interestingly, pediatric patients have reported nonpruritic urticaria.9
Urticaria also has been seen as a late dermatologic sign of viral infection. After battling relentless viral infection for 1 month, a pruritic, confluent, ill-defined eruption appeared along a patient’s trunk, back, and proximal extremities. Histopathologic examination concluded a perivascular lymphocytic infiltrate and dilated vessels in the dermis. The urticaria resolved a week later, and the patient’s nasopharyngeal swab finally came back negative.13
Vesicles mimicking those of chickenpox have been reported. A study of 375 confirmed cases of COVID-19 by Galván Casas et al12 showed a 9% incidence of this vesicular eruption. A study by Sachdeva et al8 revealed vesicular eruptions in 25 of 72 patients. Pruritic papules and vesicles may resemble Grover disease. This cutaneous sign may be seen in the submammary folds, on the hips, or diffusely over the body.