Heparin-induced skin necrosis is a rare but serious complication of subcutaneously administered heparin. Previous reports indicate that the skin necrosis is often accompanied by thrombocytopenia and occasionally by lethal thromboembolism. It thus shows features similar to the heparin-induced thrombocytopenia (HIT) syndrome and probably represents a localized form of this condition. Caution is required in the event of skin necrosis; heparin therapy should be ceased immediately and not used again if the complications of HIT are to be avoided.