Warfarin-induced skin necrosis typically occurs when?

• A. Years After Therapy
• B. During Surgery
• C. Only If Used With Heparin
• D. Shortly After Initiating Therapy With a Large Loading Dose or Without Concurrent Heparin

Answer: (D)

Warfarin-induced skin necrosis most often appears in the first few days after starting therapy, especially when a large loading dose is given without heparin bridging. The reason is that warfarin quickly lowers protein C, a natural anticoagulant with a short half-life, creating a transient hypercoagulable state. This promotes microthrombosis in skin vessels, particularly in fatty areas, leading to painful necrotic lesions. The risk is higher in patients with protein C or S deficiency. Clinically, lesions develop about 3–6 days after initiation. Management involves stopping warfarin, starting appropriate anticoagulation (often with heparin) and reversing with vitamin K as needed, with careful reconsideration of future anticoagulation and bridging strategies.