Postinfection purpura fulminans in a patient heterozygous for prothrombin G20210A and acquired protein S resistance.

Purpura fulminans usually consists of large, often symmetrical, spreading ecchymosis, which may later develop into extensive areas of skin necrosis and peripheral gangrene. Postinfectious purpura fulminans associated with an autoantibody directed against protein S has been described. The interaction and the contribution of recently described mutations such as factor V Leiden and prothrombin G20210A to the development and progression of postinfectious purpura fulminans and venous thrombosis is not known. The authors describe a patient heterozygous for prothrombin G20210A who developed purpura fulminans and extensive venous thrombosis secondary to acquired protein S deficiency.