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Blastomycosis is a rare infection that may develop when people breathe in (inhale) a fungus called Blastomyces dermatitidis, which is found in wood and soil.

North American blastomycosis; Gilchrist's disease

Blastomycosis occurs in people living in the south-central and midwestern United States and Canada. The infection is seen in 1-2 out of every 100,000 people in areas where the fungus most often occurs. It is even less common outside those areas.

Being around infected soil is the key risk factor.

The disease usually affects people with weakened immune systems, such as those with HIV or who have had an organ transplant. Men are more likely to be affected than women.

Lung infection may produce no symptoms, but when the infection spreads, skin or bone sores (lesions) may appear. The bladder, kidney, prostate, and testes may be affected.

Other symptoms may include:

• Chest pain
• Cough (may produce brown or bloody mucus)
• Fatigue
• Fever
• General discomfort, uneasiness, or ill feeling (malaise)
• Joint stiffness and pain
• Muscle stiffness and pain
• Rash
• Shortness of breath
• Sweating
• Unintentional weight loss

• Chest x-ray
• Skin biopsy
• Sputum culture and examination under the microscope after applying special stains to sputum
• Tissue biopsy

Patients with minor skin sores (lesions) and relatively mild lung infections usually recover completely. If the infection is not treated, it can become severe enough to cause death.

• Large sores with pus (abscesses)
• Return of the infection (relapse or disease recurrence)
• Side effects from drugs such as amphotericin B

Call your health care provider if you have symptoms of blastomycosis.

Avoiding travel to areas where the infection is known to occur may help prevent exposure to the fungus, but this may not always be possible.

Chapman SW. Plastomyces dermatitidis. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 6th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2005: chap 263.