Blastomycosis.

Blastomycosis is a fungal disease with an endemic area identical to that of histoplasmosis in the United States. Disease states range from a subclinical pulmonary illness to a rapidly progressive and fatal disease. Cutaneous lesions are common although the lung is the portal of entry for blastomyces. The organisms are easily demonstrated with potassium hydroxide preparations of fresh sputum, pus from skin lesions, or other biologic material. Skin and serologic tests are unreliable, largely because of cross-reactivity with antigens of histoplasmosis. Because of the ever present potential for milder forms of illness to progress to severe disease, it is recommended that all patients with symptomatic or culture proven disease be treated with amphotericin B.