Histoplasmosis in AIDS: advances in management.

Histoplasmosis is one of the most common opportunistic infections in HIV-infected patients who reside in endemic areas, and "imported infections" also occur elsewhere. A recent decline in the incidence of histoplasmosis appears to correlate with advances in antiretroviral therapy. Histoplasmosis occurs due to either dissemination of newly acquired infection or reactivation of latent foci of infection. Major risk factors include a CD4 count < or = 150/microL, positive complement fixation serology for the Histoplasma capsulatum mycelial antigen, and a history of exposure to chicken coops; in addition, suboptimal antiretroviral therapy seems likely to be a risk factor. Although there are a variety of clinical manifestations, most patients present with a several-week history of fever, chills, weakness, and weight loss. Diagnosis is based on positive cultures of blood, bone marrow, or other sites; detection of antigen in serum or urine; or characteristic histopathologic findings in biopsy specimens. Induction therapy consists of amphotericin B for acutely ill patients or itraconazole for patients with mild to moderately severe disease. Subsequent lifelong maintenance therapy with itraconazole is recommended. In patients with CD4 counts of < or = 150/microL, itraconazole is effective primary prophylaxis.