Warfarin-induced leukocytoclastic vasculitis: a case report and review of literature.

Warfarin is widely prescribed for patients with atrial fibrillation. In addition to unexpected bleeding, allergic skin reaction is one of its uncommon adverse effects. We herein report an 89-year-old man who, after taking warfarin for 4 years, suffered extensive skin eruptions. The skin biopsy disclosed leukocytoclastic vasculitis. The causal relationship between skin lesions and warfarin was confirmed after re-challenge of warfarin. A literature review revealed only 13 such cases reported from 1980 to 2011. Clinicians should be aware of this potential adverse effect of warfarin.