Blastomyces dermatitidis of the perianal skin: report of a case.

Isolated fungal infections of the perianal skin are rare and their diagnosis is frequently overlooked. We report a case of a 78-year-old male patient who presented with a friable, violaceous, papulopustular lesion, with heaped-up edges along the anal verge. Biopsy revealed unicellular yeast consistent with blastomycosis. The patient was treated with itraconazole with resolution of this lesion. An extensive MEDLINE literature review from 1958 to the present indicates that this is an uncommon manifestation of cutaneous blastomycosis. A summary of the medical literature is presented with a review of the characteristics, diagnosis, and management of blastomycosis.