Bubble Trouble

This was a case of a 63 year-old man who presented with right upper extremity edema, erythema, and pain over 1 day duration, which included 2 large bullae on the forearm. Past medical history included hypertension, gout, and hyperlipidemia. Medications included furosemide, valsartan (previous angioedema reaction to lisinopril), allopurinol, and tamsulosin. Labs were normal. Initially there was concern for a necrotizing soft-tissue infection, such as necrotizing fasciitis, though a CT did not show evidence of gas or fluid collections. The patient improved rapidly with intravenous antibiotics. Clindamycin was initially chosen for Gram positive and anaerobic coverage, as well as inhibition of potential toxin production (as clindamycin blocks transcription).

However, despite improvement on one arm, the patient developed a bulla on the contralateral arm, which was concerning for bullous pemphigoid in the setting of furosemide usage (a common cause). Antibiotics were stopped and Dermatology was called for a skin biopsy, which was performed. The patient continued to improve off antibiotics. Skin biopsy was negative for immunofluorescense, which would have confirmed the diagnosis.

Teaching Points:

–  Early surgical debridement is necessary once the diagnosis of a necrotizing soft tissue infection is confirmed; otherwise mortality approaches 100%. Antibiotics alone are insufficient.

–   Bullous pemphigoid may be associated with medications, most commonly furosemide, penicillamine, and captopril

Good reviews of necrotizing soft tissue infections and bullous pemphigoid can be found by following these links.