Warfarin-induced skin necrosis

Warfarin is a frequently used oral anticoagulant in the treatment and prevention of various medical conditions. One uncommon adverse effect that can occur following the initiation of therapy is warfarin-induced skin necrosis. Because it is a rare effect with an undetermined pathophysiology of disease, the treatment is not well established.

A 52-year-old female was prescribed warfarin and enoxaparin for a newly diagnosed deep vein thrombosis (DVT) in the left lower extremity. On day 4 of therapy, the patient had a supra-therapeutic international normalized ratio (INR), prompting the discontinuation of enoxaparin and a decrease in the warfarin dose. The patient returned to the emergency department on day 7 of treatment with a purple, cold, and extremely painful right foot with punctate areas of necrosis and petechiae proximal to the discoloration. The patient's INR was found to be 10.64. Following the diagnosis of warfarin-induced skin necrosis, the patient was administered vitamin K intravenously and fresh frozen plasma (FFP) to reverse the effects of warfarin and promote protein C and S synthesis. Once the patient's INR was no longer supratherapeutic, subcutaneous enoxaparin was re-started as treatment for the known recent DVT. The patient's necrotic foot began to improve and she was discharged home with an anticipated full recovery.

Based on the proposed pathophysiology of disease, adequate bridge therapy may decrease the likelihood of developing this life-threatening condition. Early recognition and treatment with intravenous vitamin K, FFP or 4-factor prothrombin complex concentrate, and continued wound care are essential to prevent further complications.