Some patients infected by covid-19 develop skin manifestations. These manifestations are still not well known and there pathophysiology remain unclear. Among them, acral manifestation resembling to chilblains appears frequent and quite specific. The aim of this project is to better characterize the cutaneous manifestations occurring during Covid-19 infection with a special focus on chilblains. These acral manifestation could be due to a direct viral effect, but also to microthrombosis or vascularitis. Understanding the pathomechanisms involved could provide interesting clue for understanding not only the skin manifestations but also some of the other systemic symptoms associated to covid-19 infection. This study plan to characterize these acral manifestations by analyzing the clinical and dermoscopic patterns and to correlate them with the non-invasive vascular explorations but also immune and coagulopathy explorations that are done in the CHU of Nice in covid-19 patients.