Blastomycosis checklist for dogs

Dog owners need to be alert to the possible existence of the fungal organism Blastomyces dermatitidis, which can be found in sandy, acidic soils close to water or in swampy, low-lying areas. It is especially prevalent in certain areas of Mississippi, Missouri, the Ohio River Valley, as well as the Mid-Atlantic States, but it can occur almost anywhere. The resulting systemic fungal disease, blastomycosis, is serious, affecting primarily dogs and humans. It creates a variety of symptoms. Early detection is critical to successful treatment and rate of survival.

Hunting dogs and those that love to take to the woods and swamps, or those living by water, are especially vulnerable. On a chase, with his nose to the ground, a dog can inhale spores that harbor in the soil. If the dog has a healthy immune system, there is likelihood that the disease will not develop. If, however, the spores are abundant, or if the dog’s immune system is compromised, there is risk of infection. Spores travel down the airways of the lungs, and the disease begins. It then spreads throughout the body and can affect the skin, eyes, bones, lymph nodes, subcutaneous tissue, brain, and testes. Blastomycosis can wax and wane with symptoms improving, only to worsen later.

Refer to this checklistof symptoms if you suspect your dog has been exposed to this organism:


This important checklist can be printed and shared with your veterinarian. Arriving at a diagnosis can sometimes be difficult. Your veterinarian will consider the history and symptoms and seek to identify the organism under a microscope or through a blood test. Treatment is required in the case of a positive identification because dogsare not able to fight off this fungal disease without support.

Treatment options include the oral administration of Itaconazole. This is an expensive drug, and some dogs cannot tolerate it. Injectable Amphotericin B can also be used. It is administered intravenously and under close veterinary supervision. Ketoconazole (Nizoral) is another treatment option, especially helpful in mild cases of the disease and where cost is a factor. Please note that, with Blastomycosis, prevention is easier than the cure. Avoid taking dogs to regions of high risk or incidence and places with disturbed areas of moist soil. Awareness of the disease and its symptoms is the best defense against it.

Be sure to inform your veterinarian if your dog is taking other medications or supplements. These may interact in potentially harmful ways; your veterinarian can make the best recommendation for your dog.