Nonresolving Nodular Rash

A 51-year-old woman with eczema applying topical steroids presented to the infectious diseases clinic for right hand skin lesions. She reported progression of several nodules on the dorsum of her right hand over 3 months. The nodules were enlarging, becoming more painful and pruritic, and some had developed purulent discharge. She was otherwise well and denied fevers or other constitutional symptoms. Prior to the onset of the lesions, she reported cleaning out her fish tank and backyard pool. She cleaned the fish tank after the fish had died, and some of the fish had appeared disfigured. She denied surgery or trauma to the hand, did not have a history of gardening, and denied farm or animal exposure. She did not have tattoos or body piercings near the lesions and denied injection drug use. She denied a personal or family history of tuberculosis (TB), had no TB risk factors, and had...