Coumarin-induced skin necrosis following heparin-induced thrombocytopenia and thrombosis. A case report.

A severe thrombotic thrombocytopenic status, induced by heparin in a sixty-nine-year-old woman undergoing total hip joint arthroplasty, was treated by switching the anticoagulant therapy to coumarin, which induced skin necrosis. There appeared to be a possible causal relation between the severe immune reaction to heparin and the condition that predisposed to skin necrosis in the presence of coumarin. In patients who express a strong immune response to heparin, a different anticoagulant approach other than use of coumarin congeners appears to be justified.