Blastomycosis in Humans

Blastomycosis is thought to be a rare fungal infection caused by inhaling inhaling a fungus (Blastomyces dermatitidis), which is found in wood and soil. People thought to be at risk are those who are often associated with outdoor activities like camping, logging, and hunting. Some people have become infected by working in their crawl spaces or under the decks in known infection areas like Kenora, Ontario.

In humans, blastomycosis is also known as Gilchrist's disease, Gilchrist’s mycosis, Blastomyces dermatitidis, and Chicago disease.

In areas where blastomycosis is known to occur, the incidence of blastomycosis is 1-2 out of every 100,000 people. Men seem to get blastomycosis more often than women. Immuno-suppressed men are the most at risk.

Symptoms in Humans

  • coughing (the sputum may be brown or bloody
  • skin lesions, or small draining ulcer(s) on the skin, like a small abscess - draining bloody or purulent (pus) material - found most common on the face, neck, and the extremities.
  • shortness of breath
  • fever
  • fatigue
  • malaise
  • chills
  • joint and muscle pain
  • joint and muscle stiffness
  • rash
  • chest pain
  • prostate pain, or pain during urination

Diagnosis

There are a few methods used to diagnose Blastomycosis in a person. Often a chest x-ray is often taken. It may show nodules or pneumonia looking cavities in the lungs. A biopsy may be taken from a skin lesion. A culture can be taken of sputum as it is coughed up. Sputum cultures are not completely reliable as the culture observation can occur as early as 5 days or as late as 30 days.

A person may not even know they have blastomycosis as the lung infection caused by the fungus is not always symptomatic until it becomes quite severe.

The lesions, shown in Chris's story, are characterized by papules or papulopustules which develop into crusted, warty eruptions, and oozing sinuses.

Progression

Humans usually inhale the blastomycosis spores to become infected. Once the spores are in the lungs, the conidia transform into a yeast phase due to the warm temperature within the lungs. Then they multiply and spread through the blood and lymphatic system to other organs.

40% of human blastomycosis involve the skin.

Treatment

Antifungal medications are necessary to treat blastomycosis, such as amphotericin B, and itraconazole. Antibiotics are used to clear up infections in the lungs, on the skin, or within other organs should the blastomycosis spread outside of the lungs. Blastomycosis has spread to the bladder, kidneys, prostate, and testes. The bones can also be affected.

Prognosis

A Blastomycosis diagnosis is CRUCIAL to the patient's outcome and survival. Even then, if the fungal infection has spread too deeply within the lungs, and to other organs and tissues, the patient may not survive. Treatment and monitoring should be on-going because blastomycosis patients can have relapses during their recovery.

Blastomycosis Lesion - Back, Close Up: Blastomycosis - Back - Close Up
Blastomycosis Lesion - Left Elbow Blastomycosis - Left Elbow
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