An Immunocompromised Patient With Recent-Onset Skin Lesions

A 53-year-old gayman undergoing treatment for multiple sclerosis had received 2 doses of rituximab, with the last being 3 weeks prior to being hospitalized for worsening lower extremity weakness. He received high-dose intravenous methylprednisolone when he entered the hospital. One week before admission, he noticed tender skin eruptions adjacent to the anus and on the left shin. His physician had prescribed a combination cream of betamethasone diproprionate and clotrimazole for these lesions. The patient reportedno fevers or chills. Hehadnohistory of eczemaandhadnot used any special wipes or cleansing agents in the perianal area. Hewas not aware of any lower leg injury but did note that the shin rash had started as a “bump” that developed a central scab. He did not recall having skin lesions of this type previously. Onphysical examination anerythematous, induratedplaquewith a central blackhemorrhagic crust surrounded by yellow pustulovesicles was seen on the left shin. Adjacent to and surrounding the anus therewas an area of erythemawith irregularmargins and superficial exfoliation (Figure). Quiz at jama.com Figure.