Erythema Multiforme-like/Target-like Lesions
EM-like or target-like lesions associated with SARS-CoV-2 are hypersensitivity reactions with mucocutaneous manifestations and are seen in both children and adults. In about 90% of cases, EM lesions are usually due to infectious agents like herpes simplex virus or mycoplasma pneumonia. Other agents causing these lesions include Epstein-Barr virus, coxsackie, parvovirus, medications, and sometimes vaccines.
EM-like lesions are uncommonly reported in patients infected with SARS-CoV-2. In a case report of 22 children with CBLL, four patients presented with EM lesions, with one child who tested positive for SARS-CoV-2 by PCR testing. EM-like lesions associated with SARS-CoV-2 occur on acral areas including palms, elbows, and knees in children with target (3 rings) or targetoid (2 rings) confluent macules, papules, and plaques of varying sizes with hemorrhages and central crusts (Figure 3).[13,30] In older adults, these lesions are widespread with palatal macules and petechiae that spare the palms and soles. They self-resolve within 1–3 weeks without scarring.
EM lesions are due to a hypersensitivity reaction caused by lymphocytes and cytokines targeting SARS-CoV-2 antigens at cutaneous and mucosal sites. The SARS-CoV-2 EM lesions found in children may be a clinical variant of CBLL, as they are not consistent with histopathological features of true EM. On the other hand, SARS-CoV-2 EM lesions found in adults may be a delayed response as these lesions appeared after recovery from SARS-CoV-2 infection.
In children, acral EM-like lesions showed superficial and deep perivascular perieccrine CD3+/CD4+/CD8+ lymphocytic infiltrate with perieccrine involvement and scattered vasculopathic changes, similar to that seen in CBLL. In addition, immunohistochemical staining was positive for SARS-CoV-2 spike protein in endothelial and epithelial cells of eccrine glands.
In adults, diffuse EM-like lesions were more consistent with true EM as they showed spongiosis, lymphocytic exocytosis, interface dermatitis, and focal necrotic keratinocytes.
Children with EM-like lesions from SARS-CoV-2 have good prognosis with supportive treatment. Older adults with diffuse EM-like lesions tend to have severe SARS-CoV-2 clinical outcomes.
Am J Clin Dermatol. 2022;23(3):277-286. © 2022 Adis Springer International Publishing AG