A bullous neutrophilic dermatosis in a patient with severe rheumatoid arthritis and monoclonal IgA gammopathy

A 35-year-old man presented with a 2-month history of itchy grouped vesiculobullae with crusted papules and confluent plaques, distributed symmetrically on the thighs, knees, and elbows. The man had experienced severe disabling seropositive rheumatoid arthritis for 18 years previously. Histologically, subepidermal vesicles were noted, and a dense, diffuse neutrophilic infiltration of the dermis. Direct immunofluorescence studies did not detect IgA deposits. The patient responded well to dapsone (100 mg/d) but not to systemic steroids. This patient's eruption might have been an unusual manifestation of rheumatoid neutrophilic dermatitis.