What is Blastomycosis?

Blastomycosis is a rare fungal infection caused by Blastomyces dermatitidis. This fungus is endemic to Northern and Central American woodlands, and the majority of blastomycosis infections occur in the fall. In addition to occurring in humans, this infection can also be a problem for dogs and cats which spend time outdoors. In all cases, the treatment is the same. Very few cases of this disease are reported annually, and blastomycosis should not be a major concern for most people.

In some patients, blastomycosis produces no symptoms, and the infection may be discovered accidentally during an evaluation for another medical problem. In other instances, colonization by the fungus causes lung, skin, or bone infections. Some patients can also experience infections of the internal organs. If the blastomycosis infection is left untreated, the patient will eventually die. Immunocompromised patients are at increased risk of developing the disease, and they are also more likely to die from it.

Patients can experience fever, chills, coughing, joint pain, chest pain, and the development of distinctive lesions on the skin with this fungal infection. A doctor can diagnose blastomycosis with the assistance of a culture which will identify the fungus. After taking an extended course of antifungal drugs, the patient should be cured, although he or she may experience lingering health problems as a result of damage caused by the infection.

Typically, people develop the infection as a result of airborne exposure. Gardeners and people who work in the woods such as foresters and hunters are most at risk, because they may disturb and inhale the fungus in the course of their work. People can also be exposed by handling contaminated soil, which may cause spores to enter cuts and scrapes on the hands.

This condition is sometimes referred to as Gilchrist's disease, after an early medical researcher who identified and described it. People can reduce their risk of being infected with Blastomyces dermatitidis by wearing gloves when they handle soil in areas known to be contaminated, and by using face masks for tasks which may disturb fungal colonies, such as digging in the woods or handling brush.

Cases of blastomycosis do not appear to pass between people or animals, which means that if one person or animal in a household is infected, others probably will not carry the fungus. In regions where blastomycosis outbreaks are common, people may want to consider confining animals indoors in the fall, or taking special care when working outdoors in fall weather.