A 36-year-old African-American man was hospitalized because of a 2-week history of alternating bright red and tarry stools, vomiting, anorexia, lower leg edema, fever, and a desquamating eruption. Four months previously, during the course of evaluation for fever and cough, the patient had been discovered to be seropositive for the human immunodeficiency virus (HIV): bronchoscopy had revealed acid-fast bacilli. No cultures were performed at that time. He had been started on isoniazid, rifampin, ethambutol, and zidovudine. Although he denied intravenous drug use and other HIV risk factors, he admitted to cocaine addiction. He also denied any previous history of atopic dermatitis, psoriasis, or seborrheic dermatitis. Physical examination revealed an emaciated man with irregular, erythematous, hyperpigmented papules and plaques covering the trunk, face, arms, legs, palms, and soles; some of the lesions showed fine desquamation (Figs 1 and 2). The plaques were frequently coalescent. Several gluteal ulcerations were noted. The extremities demonstrated pitting edema. Diffuse lymphadenopathy was present. Laboratory studies showed a white blood cell count of 2100/mm(3), with 87% segmented neutrophils, 2% bands, 6% lymphocytes, 3% monocytes, and 2% eosinophils. A chest X-ray showed no abnormalities. The stool was positive for occult blood, but negative for ova and parasites. The patient's hospital course was difficult and downward. The plaques grew and further coalesced, eventually leading to an exfoliative dermatitis (erythroderma). He was initially treated empirically with intravenous ceftazidime, and then with amikacin and vancomycin after blood cultures revealed enterococci. A culture of his gluteal ulcerations yielded herpes simplex virus, but the ulcerations were unresponsive to intravenous acyclovir. A skin biopsy of the left deltoid showed a mixture of lymphocytes, histiocytes, and neutrophils infiltrating the superficial and deep dermis, including periadnexal areas. Patchy extravasation of erythrocytes was noted in the superficial dermis. Stains for spirochetes, acid-fast bacilli, and other bacteria were negative. A periodic acid-Schiff (PAS) stain showed numerous round organisms measuring 1-2 mum in diameter and located within histiocytes (Fig. 3). The morphology of these organisms was consistent with Histoplasma capsulatum. The bone marrow was hypercellular, with an overall cellularity of 60%. Gomori's methonamine silver (GMS) stain showed numerous fungi. The patient was started on amphotericin B, but the drug was soon discontinued because of worsening renal failure. Despite aggressive antibacterial, antifungal, and antiviral therapy, as well as transfusions for severe anemia, the patient continued to spike fevers and generally deteriorate. He died 11 days after admission.