Risk factors for disseminated or fatal histoplasmosis. Analysis of a large urban outbreak.

An outbreak of histoplasmosis in Indianapolis involving 488 clinically recognized cases including 60 patients with disseminated or fatal infection permitted statistical analysis of risk factors. Being male, white, under 5 years of age, having chronic obstructive lung disease, and living near the presumed source of the outbreak were not risk factors for fatal or disseminated histoplasmosis. Age greater than 54 years and immunosuppression were the only risk factors for disseminated or fatal infection. Dissemination should be excluded in patients with histoplasmosis who are immunosuppressed or older than 54 years. Specific antifungal treatment is more likely to be required in those two groups rather than in patients without risk factors.