[Vascular emergencies in dermatology].

Life-threatening vascular complications of the skin are rare and usually reflect underlying systemic diseases. Lesions are sudden in onset, become necrotic and may be severe or life-threatening. Effective management requires an understanding of the underlying medical condition, such as arterial thrombosis, temporal arteritis, calciphylaxis and purpura fulminans. In contrast, the acute painful symptoms of erythromelalgia often lead to an urgent dermatologic consultation but pose no acute risk.