North American blastomycosis, Blastomycetic dermatitis, Gilchrist's Disease
What is Blastomycosis?
Blastomycosis is a chronic fungal infection of the lung that often spreads to the skin or bones. It is most commonly seen in men in Midwestern North America. The infection is caused by the fungus Blastomyces dermatitidis, a fungus normally found in soil. Anything that disturbs the soil, such as plowing or heavy construction, can disperse the fungus into the air where it is inhaled. Person-to-person spread of blastomycosis can also occur by direct contact with skin lesions. The initial infection may be asymptomatic, allowing the infection to spread or enabling individuals to travel great distances from the source of infection before detection. Treatment with antifungal drugs is highly effective.
How is Blastomycosis diagnosed?
- History may include a profession such as farmer or construction worker. Symptoms of blastomycosis in the lung include cough, chest pain, weight loss, and a moderate fever. Skin ulcers may be reported. Bone or joint pain may be present, if the infection has spread to these areas.
- Physical exam confirms the fever. The lungs may have the abnormal breath sounds of chronic pneumonia. Skin lesions, typically on the hands, arms, legs, or face, appear wart-like or as ulcers. Bone or joint infection will have local tenderness and swelling. Inflammation of the prostate and testicle may be present.
- Tests: B. dermatitidis may be identified microscopically from sputum or skin lesions, or by culture. Blood or skin tests are not accurate indicators of infection. Chest x-ray may reveal infiltrates and pneumonia. X-ray of a bone infection can show areas of bone destruction.
Blastomycosis signs and symptoms
- Symptoms may begin slowly or infection may be abrupt.
- Cough, either dry and non-productive or with sputum.
- Chest pain.
- Chills, fever and drenching sweats.
- Shortness of breath.
- Fatigue, loss of apetite.
- If skin involved, may have lesions or abscesses.
Infection with the fungus, Blastomyces dermatitidis, found in wood and soil. There may be some association with beaver huts. Skin lesions occur most commonly in gardeners or farmers, but the natural source of this fungus is unknown.
Risk increases with
- Gardening and farming, especially in Southeastern states and the Mississippi River valley of the U.S.
- Diabetes mellitus.
- Use of immunosuppressive drugs.
What might complicate it?
Scarring of lung tissues may lead to chronic respiratory insufficiencies. Infection in bones may destroy the bone if allowed to progress. If vertebrae or long bones are involved, the infection may result in loss of physical function. Untreated skin lesions may lead to the formation of extensively scarred tissue.
The prognosis is good if treatment is begun early. Most infections will resolve with treatment. Advanced bone disease or, rarely, brain involvement will lengthen disability and chance of complete recovery.
Chronic skin lesions may resemble skin cancer. Other fungal infections may cause skin lesions. Respiratory blastomycosis may resemble tuberculosis or other fungal infections of the lungs.
How is Blastomycosis treated?
Blastomycosis is treated with anti-infective drugs for at least two to three months. Anti-inflammatory drugs may be used to decrease pain and inflammation. Follow-up exams for several years should be done to detect a recurrence of the disease.
Rest in bed during the acute stage. Resume activities gradually as your strength returns.
No special diet.
Infectious disease specialist, dermatologist and pulmonary disease specialist.
Notify your physician if
- You or a family member has symptoms of blastomycosis.
- Any of the following occur during treatment:
- Weight loss.
- Diarrhea that cannot be controlled with home remedies.
- Severe headache and stiff neck.
- New, unexplained symptoms develop. Drugs used in treatment may produce side effects.
Last updated 20 December 2021