Hemorrhagic bullous dermatosis caused by warfarin therapy

Fig 1. Papules with overlying hemorrhagic crusting located on the proximal arm (underlying bruising is caused by recent trauma to the arm and is not a result of the patient’s hemorrhagic bullous dermatosis). INTRODUCTION Hemorrhagic bullous dermatosis is a rare, generalized skin reaction with unknown pathogenesis, described in association with heparin therapy. Heparin is known to cause injection site reactions and ecchymosis but rarely causes global cutaneous reactions, making hemorrhagic bullous dermatosis an unusual clinical entity. The condition occurs within 5 to 21 days of the initiation of therapy at locations distant to the site of subcutaneous heparin injection. Characteristic lesions are painless, hemorrhagic papules on a background of uninvolved skin. The histologic findings are usually nonspecific but can help rule out thrombosis, vasculitis, or marked inflammatory changes. Skin lesions usually resolve after discontinuation of heparin. We present a case of hemorrhagic bullous dermatosis in an 82-year-old woman recently started on warfarin therapy and briefly review skin effects of anticoagulation.