Don’t wait and see
Up to half of dogs with severe lung disease die in the first week of treatment. If your dog has a cough or labored breathing plus weight loss, fever, eye trouble, skin sores or limping, and especially if a “pneumonia” isn’t improving on antibiotics, ask your vet today about a Blastomyces urine antigen test.
Warning signs
Blastomycosis often affects several parts of the body at once. Approximate share of sick dogs showing each sign:
- Lungs (up to 85% of dogs): cough, fast or hard breathing, tiring easily, raspy breath sounds
- Lymph nodes (about half): lumps under the jaw, in front of the shoulders or behind the knees
- Skin (about half): raised bumps or draining sores, often on the nose, face or nail beds
- Eyes (30–50%): redness, squinting, cloudiness, sudden blindness
- Whole body: fever over 103°F (40–60% of dogs), weight loss, poor appetite, low energy
- Bones (about 1 in 4): limping or a swollen leg
- Brain (under 5%): seizures, circling, behavior changes
Cases are diagnosed most often in late summer and fall, but they can happen any time of year.
What to do if you think your dog has blasto
- Call your vet today. If your dog is struggling to breathe, breathing fast at rest, or has gums that look pale or bluish, go to an emergency vet now. Dogs with severe lung disease can get worse within days.
- Say the word “blastomycosis.” Many vets outside the Midwest don’t think of it first. Tell them you’re worried about it and why.
- Share where your dog has been in the past few months: rivers, ponds, lake shores, wet woods, beaver areas, construction sites, flooded ground, and any travel.
- Ask about testing: a Blastomyces urine antigen test, chest X-rays, and a needle sample of any lump, swollen lymph node or skin sore. Mention it if antibiotics haven’t helped.
- If it’s confirmed, start treatment right away and ask for FDA-approved itraconazole (brand or generic), not a compounded version. In a 2018 study of 115 treated pets, 95% of those on compounded itraconazole had blood levels too low to work. Ask your vet whether a blood test to check the drug level makes sense.
- Finish the full course, which usually runs for months, and keep every recheck. About 1 in 5 dogs relapse, usually within 6 months of stopping, so watch for returning signs.
- Protect your household. Your dog can’t give it to you, but you shared the same ground. Watch your other pets, wear gloves when cleaning draining sores, and tell your own doctor about the diagnosis if anyone in your home gets a lasting cough or fever.
- Warn your neighbors who walk the same trails or riverbanks.
Which dogs are most at risk
- Dogs that live or roam near water. Most affected dogs live within 400 meters (a quarter mile) of a river, lake or stream.
- Young adult, large-breed dogs, typically 2 to 4 years old. Some studies find males slightly more often.
- Sporting and hound breeds, such as coonhounds, pointers, Weimaraners, retrievers and Doberman pinschers. Any breed can get it.
- Dogs that spend a lot of time outdoors, hunting, hiking, swimming, digging, or near recent excavation. Indoor dogs can get it too.
How vets diagnose it
- Urine antigen test. A sensitive, non-invasive test sent to a specialty lab (MiraVista Diagnostics runs one). It can cross-react with a related fungus, histoplasmosis, and a negative result doesn’t fully rule out early or mild disease.
- Chest X-rays. Often show a scattered “snowstorm” pattern and enlarged lymph nodes in the chest.
- Finding the yeast. A needle sample from a lymph node, skin sore, eye or lung, looked at under a microscope.
Questions to ask your vet
- Could this be blastomycosis or another fungal infection?
- Can we run a Blastomyces urine antigen test?
- Should we take chest X-rays?
- If antibiotics haven’t helped, what else could explain it?
Tell your vet everywhere your dog has been in the past few months: rivers, ponds, woods, construction sites, and any travel.
Treatment
- Itraconazole, an oral antifungal, is the usual first choice. Treatment lasts at least 3 months and often 4 to 6 months or longer.
- Fluconazole is cheaper but less effective. Amphotericin B, given by IV, is used for severe or life-threatening cases.
- Dogs with serious lung disease may need hospital care and oxygen. Their breathing can get worse in the first few days of treatment as the fungus dies off.
- Vets usually keep treating until repeat urine antigen tests come back negative, then recheck afterward.
Outlook
- With prompt treatment, roughly 50–80% of dogs recover. In severe cases, up to half of dogs with serious lung disease die within the first week of treatment.
- The outlook is best with mild lung disease, more guarded with severe lung disease, and poorest if the brain is involved.
- About 1 in 5 dogs relapse, usually within 6 months of stopping treatment. A second course cures most of them.
If you’ve lost a dog you think had blasto
Ask your vet whether tests or a post-mortem exam (necropsy) were done, or can still be done, to confirm the cause. Any other dogs in your home shared the same ground, so watch them closely for the signs above. And tell your own doctor if anyone in the household develops a lingering cough or fever.
Keep reading: How dogs catch it · Protecting your dog · What it looks like in people
Blasto Awareness shares public information for awareness only. It is not veterinary advice; your vet decides on testing and treatment. Sources: Merck Veterinary Manual; MiraVista Diagnostics; dvm360 (Gaunt & Taylor); Purina Pro Club; Ontario Animal Health Network. Full list on the Sources page.