COVID-19 and cutaneous manifestations: a systematic review.

The cutaneous manifestations of COVID-19 patients have been increasingly reported, but not summarized, and the potential mechanisms remain to be investigated. Herein, we performed a comprehensive review of literatures (from inception to 30 May 2020) using PubMed, CNKI, medRxiv and bioRxiv with the terms "((novel coronavirus) OR (2019 novel coronavirus) OR (2019-nCoV) OR (Coronavirus disease 2019) OR (COVID-19) OR (SARS-CoV-2)) AND ((Dermatology) OR (skin) OR (rash) OR (cutaneous))" and "((ACE2) OR (Angiotensin-converting enzyme)) AND ((skin) OR (epidermis) OR (dermis))." Totally, 44 articles met the inclusion criteria. A total of 507 patients with cutaneous manifestations were summarized, and 96.25% patients were from Europe. The average age of the patients was 49.03 (range: 5-91) with a female ratio of 60.44%. The skin lesions were polymorphic, and erythema, chilblain-like and urticarial lesions were most common, occurring on an average of 9.92 days (range: 1-30) after the onset of systemic symptoms. The receptor of SARS-CoV-2, ACE2, was found to be expressed on skin, mainly on keratinocytes. Our review systematically presented the clinical characteristics of 507 patients and showed that skin might be the potential target of the infection according to ACE2 expression. More work should be done to better understand the underlying pathogenesis.