1. Skin manifestations similar to those in other viral infections
During the COVID-19 outbreak in China, it was not a focus to document skin manifestations. Consequently, skin rash has only been reported in 2 out of 1.099 infected patients (0.2%) (21). In contrast, a study by dermatologists from Italy reported skin manifestations in 18/88 patients (20.4%) with COVID-19 (4). Cutaneous manifestations seen were either erythematous rash (n=14), widespread urticaria (n=3), or chickenpox-like vesicular rash (n=1). In Spain, among 375 patients with suspected or confirmed COVID-19, maculopapular eruptions (MPEs), sometimes similar to pityriasis rosea, were observed in 47% of the cases, urticarial lesions in 19% and vesicular eruptions of the trunk in 9% (22). Another case of urticaria was presented in France (Figure 2A)(23) and patients with morbilliform exanthem in the USA (Figure 2B)(24). Varicella-like lesions predominantly on the trunk were described in 22 patients with proven COVID-19 infection in Italy (25). Predominance of vesicles was reported in 54.5% and generally mild itching in nine (40.9%) patients. The vesiculopapular exanthem appears to develop early in the course of the disease (Figure 2C (26))(22,26). Two patients with bilateral flexural exanthems resembling systemic drug-related intertriginous exanthems (SDRIFE), one with axillary purpuric lesions associated with thrombocytopenia, have been published (Figure 2D) (27). A prospective study from France reported a prevalence of 5/103 (4.9%) and confirmed association of pruritic erythematous rash (n=2) and urticaria (n=2) with COVID-19 infections (28); they additionally observed one oral herpes simplex virus type 1 reactivation. The histopathological picture of exanthematic skin lesions generally resembles that of viral exanthems. However, in individual patients, early microthrombi and an interface dermatitis with necrotic keratinocytes surrounded by lymphocytes have been reported (29).