Nail Manifestations in COVID-19: Insight into a Systemic Viral Disease.

Nail manifestations are 1 of the several extrapulmonary findings associated with COVID-19 caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Nail changes, however, have been largely ignored and not yet summarized. This article is intended to increase awareness of nail manifestations of SARS-CoV-2, which occur weeks to months after acute infection and the periungual pernio-like changes may occur concomitantly with infection. An electronic search was carried out in PubMed (Medline), Science Direct, and Scopus databases. The following keywords and all of their possible combinations were used to identify studies: "SARS-CoV-2," "COVID-19," "Coronavirus," "2019-ncov," "nail," and "nails." Six case reports were included in this study. Manifestations identified included red half-moon sign, transverse orange nail lesions, Mees' lines, and Beau's lines. Though largely nonspecific, these findings can be recognized with the onset of symptom onset or as late as 16 weeks following the disease. Some of these findings are shared with other conditions associated with a proinflammatory state. Nail changes offer unique insight into the pathophysiologic basis for SARS-CoV-2 and they may serve as diagnostic clues.