Bullous hemorrhagic dermatosis (BHD) is a non-life-threatening side-effect from administration of low-molecular weight heparin (eg, enoxaparin, dalteparin, tinzaparin, bemiparin), heparin, and unfractionated heparin, characterized by multiple tense, blood-filled vesicles or bullae near or distant from the site of injection. It is most commonly associated with enoxaparin use, which accounts for over 60% of cases reported in the literature. BHD has also been reported with fondaparinux and warfarin use.

Those affected are typically in their 60s to 80s, which may reflect the typical age of anticoagulant use, with a male to female ratio of 1.9 to 1. The lesions typically appear 2-20 days (median 7 days) after initiation of anticoagulant treatment. There are over 90 cases reported in literature, but BHD may be underreported.

The etiology of BHD is poorly understood.