Blastomycosis, or blasto as it is often called, is a fungal disease that most commonly affects dogs. Blasto organisms live in moist soil, especially in Mississippi, Ohio, Missouri, Tennessee, the St. Lawrence River valley, the Mid-Atlantic states, Quebec, Ontario, Manitoba, and along the southern Great Lakes. Dogs usually become sick after inhaling Blastomyces spores, but they can also develop infections through open skin wounds.
"With prompt diagnosis and early and aggressive treatment, most dogs that develop blastomycosis can survive their infections and have a good quality of life."
Signs of Blastomycosis
After blasto has gained entry to the body, it can travel almost anywhere and cause a variety of symptoms depending on where the infection localizes. Commonly, dogs have some combination of poor appetite, weight loss, coughing, difficulty breathing, limping (often from bone infections), eye problems, skin lesions (particularly around the nails), enlarged lymph nodes, and fever. If the organism infects the brain, seizures and other neurological problems may also develop.
The symptoms of blastomycosis are not unique to this disease. After taking a thorough history (including information about travel to or residence in endemic areas) and performing a physical examination, a veterinarian may suspect blastomycosis, but he or she will typically run a blood chemistry panel, complete blood cell count, a urinalysis, and X-rays to rule out other more common causes of a dog’s clinical signs. Serologic tests can support a diagnosis of blastomycosis, but finding the organism in fluid or tissue samples taken from the patient is the best way to reach a definitive diagnosis.
Once blastomycosis has been diagnosed, treatment with anti-fungal medications should begin immediately. Itraconazole is the drug of choice, but under certain circumstance other drugs like fluconazole or amphotericin might be considered as well.
Supportive therapy (e.g., intravenous fluids, oxygen, and nutritional support), pain relief, and other medications may be needed in severe cases. Blastomycosis of the eye is especially difficult to treat. Veterinarians may prescribe topical and/or systemic corticosteroids in addition to anti-fungal medications in an attempt to salvage eyesight or recommend that a permanently blind eye be surgically removed.
Home Care for Blasto
Even with appropriate treatment, dogs may not show signs of improvement for a week or two, and the long term use of anti-fungal medications is essential to a positive outcome. Most dogs need to be treated for at least two or three months or even longer depending on the severity of the disease and which drug is used. Close monitoring via check-ups, repeat X-rays, and/or blood tests should continue during and after treatment because approximately 15-20% of dogs experience a relapse within 6 months of stopping therapy.
With prompt diagnosis and early and aggressive treatment, most dogs that develop blastomycosis can survive their infections and have a good quality of life for the rest of their years.
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