Coumarin-induced skin necrosis.

Coumarin skin necrosis is a rare and usually unpredictable complication of coumarin therapy, occasionally leading to death. Onset is usually between the third and sixth day of coumarin therapy. The patient most commonly complains of pain in a region of abundant subcutaneous fat, with progression to erythema, petechiae, and gangrenous necrosis. Thrombosis of the dermal and the subcutaneous veins is demonstrated pathologically. We describe a case and review the pathogenesis, treatment, and prevention of this lesion.