A Window into the Vascular Endothelium in Covid-19: Nails.

INTRODUCTION: Endothelial damage is associated with acute and long-term coronavirus disease 2019 (COVID-19) complications. Proximal nailfold capillaries and nail beds give important clues to microvascular changes associated with endothelial dysfunction. OBJECTIVE: We aimed to use dermoscopy to examine the proximal nailfold capillaries and nail bed of COVID-19 patients and identify microvascular changes. METHODS: A prospective study was designed to evaluate the dermoscopic features of proximal nail fold capillaries and nail bed in mild-to-moderate COVID-19 patients and healthy controls between June 2022 and December 2023. The patients underwent their initial dermoscopic examination two weeks after the onset of symptoms, followed by a follow-up evaluation 10-14 months later. RESULTS: The study included 46 patients with mild-to-moderate COVID-19 and 62 healthy controls. The presence of avascular areas (P <0.001), meandering capillaries (P = 0.016), microhemorrhages (P = 0.007), and enlarged capillaries (P = 0.009) in the proximal nail fold was significantly higher in COVID-19 patients than in healthy controls. The capillary architecture was disorganized (P = 0.002) and density reduced (P <0.001) in COVID-19 patients compared to healthy controls. In the follow-up examination, microvascular changes were observed to have regressed. CONCLUSIONS: Proximal nailfold dermoscopy is an effective, low-cost, easily accessible method that enables observation of microvascular changes in COVID-19 patients.