Warfarin skin necrosis in a postpartum woman with protein S deficiency

BACKGROUND: Warfarin-induced skin necrosis is a rare and dangerous complication affecting 0.01-0.1% of patients on warfarin. Deficiencies in protein C or protein S in association with other factors have been implicated in its etiology. No report has described this disorder in the immediate postpartum period in patients with protein S deficiency. CASE: A 1-week postpartum woman with known protein S deficiency presented with skin necrosis after a previously uneventful course of warfarin. CONCLUSION: Reduced levels of free protein S during the antepartum and immediate postpartum periods predispose protein S-deficient women to warfarin skin necrosis. Previously uncomplicated courses of warfarin do not obviate the possibility of skin necrosis with future warfarin administrations. Initiation of low-dose warfarin with heparin can reduce the likelihood of this disorder.