Blastomycosis in Dogs

Blastomycosis in Dogs

Discover everything about blastomycosis in dogs, including symptoms, how it's diagnosed, treatment options, and tips for prevention. Learn how to protect your pet from this fungal infection.

Table of Contents

Blastomycosis is a serious fungal infection that can affect dogs, especially those who love to dig in the soil or who live in areas where the fungus Blastomyces dermatitidis thrives. This condition can lead to severe health issues and, if not treated promptly, can even be fatal. Understanding the causes, symptoms, and treatment options for blastomycosis in dogs is essential for pet owners to ensure their furry friends remain healthy and happy.

What is Blastomycosis?

Blastomycosis is caused by the fungus Blastomyces dermatitidis, which is found in moist soil and decomposing organic matter such as wood and leaves. The fungus releases spores into the air, and infection occurs when a dog inhales these microscopic spores. Once inside the lungs, the spores transform into yeast and can spread to other parts of the body, including the eyes, skin, and bones.

Geographic Prevalence

Blastomycosis is most commonly found in North America, particularly in the southeastern United States, the Mississippi River valley, the Great Lakes region, and parts of Canada. Dogs that live in or travel to these areas are at a higher risk of contracting the disease.

Symptoms of Blastomycosis in Dogs

The symptoms of blastomycosis in dogs can vary widely and depend on which part of the body is affected. Common signs include:

  • Respiratory Issues: Coughing, wheezing, and difficulty breathing are common in dogs affected by blastomycosis.
  • Eye Problems: Inflammation, discharge, and even blindness can occur if the infection spreads to the eyes.
  • Skin Lesions: The fungus can cause crusty or oozing sores on the skin, often with a distinctive raised edge.
  • Lethargy and Weight Loss: Infected dogs may show a lack of energy and a decrease in appetite.
  • Lameness: If the infection spreads to the bones or joints, it can cause pain and limping.
Blastomycosis in Dogs - Symptoms and Diagnosis
Blastomycosis in Dogs – Symptoms and Diagnosis

Diagnosing Blastomycosis in Dogs

Diagnosing blastomycosis in dogs can be challenging due to the varied symptoms and the similarity of these symptoms to other diseases. Veterinarians will typically perform a combination of blood tests, urine tests, imaging studies like X-rays or CT scans, and sometimes tissue biopsies to confirm the presence of the Blastomyces fungus.

Treating Blastomycosis in Dogs

Treatment for blastomycosis usually involves antifungal medications, which can be quite effective but may need to be administered for several months. The most commonly used antifungal drugs are itraconazole and fluconazole. In severe cases, amphotericin B may be used, but it has more potential side effects.

Early detection and treatment are crucial for a positive outcome. Without treatment, blastomycosis can be fatal, especially if it spreads beyond the lungs.


Preventing blastomycosis can be difficult since avoiding the outdoors is not practical for most dogs. However, awareness of the environments where the fungus thrives can help in minimizing exposure. Keeping dogs away from wet, wooded areas known to harbor the fungus, especially in the geographic regions mentioned, can reduce the risk of infection.

Long-term Outlook

The long-term outlook for dogs treated for blastomycosis is generally good, provided the disease is caught early and treated aggressively. However, there can be complications, especially if the infection has spread to the eyes or central nervous system. Regular follow-ups with a veterinarian are essential to monitor the dog’s recovery and to adjust treatment as needed.

Blastomycosis is a serious but treatable condition in dogs. Awareness of the symptoms, regions where the fungus is prevalent, and understanding the need for prompt veterinary care can help keep dogs safe from this dangerous infection. By staying vigilant and informed, dog owners can help protect their pets from blastomycosis and ensure they lead long, healthy lives.

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