Why Isn't Your Dog's Cough Responding to Antibiotics?
A cough that won't quit, weight loss, and no response to antibiotics. Here's what fungal pneumonia looks like in dogs.
If your dog has had a cough that won’t quit, is losing weight, and seems more tired than usual, and antibiotics haven’t helped, your vet may start investigating fungal pneumonia. Here’s what that actually means: fungal pneumonia is a lung infection caused by inhaled fungal spores from the soil. It’s not bacterial, it’s not contagious, and antibiotics won’t touch it.
It’s serious and can take months to treat, but it’s very manageable when caught and handled the right way.
TL;DR
- Fungal pneumonia in dogs is a lung infection caused by breathing in fungal spores from the environment, not from other dogs or people.
- The most common culprits are Blastomyces, Histoplasma, and Coccidioides (the fungus behind Valley Fever), each tied to specific regions of the U.S.
- Signs include a chronic cough, difficulty breathing, fever, weight loss, and lethargy, and diagnosis typically involves chest X-rays and fungal titer blood tests.
- Treatment means long courses of antifungal medication like itraconazole or fluconazole, sometimes for six months or more, and costs can add up fast.
- Enrolling in Lemonade Pet insurance before symptoms appear means a covered illness won’t become a financial emergency on top of an already stressful situation.
What is fungal pneumonia in dogs?
Fungal pneumonia is what happens when a dog inhales microscopic fungal spores that then take hold in the lungs and cause a serious infection. It’s different from the bacterial pneumonia most people have heard of. Antibiotics won’t touch it. The fungi responsible live in soil and organic debris, and most dogs get exposed simply by being outside, sniffing around, or digging in contaminated ground.
The three main fungi behind this condition are:
- Blastomyces dermatitidis: The fungus behind blastomycosis, found in moist, sandy, or wooded soil near waterways
- Histoplasma capsulatum: Which causes histoplasmosis and thrives in soil enriched by bird or bat droppings
- Coccidioides immitis: The fungus behind coccidioidomycosis, commonly called Valley Fever, which lives in dry, dusty desert soil
Once inhaled, the spores can settle into the lungs and, in some cases, spread through the bloodstream to other parts of the body, including the eyes, skin, and bones. That’s why fungal pneumonia can sometimes look like several different problems at once.
What are the symptoms of fungal pneumonia in dogs?
The signs often build slowly, which is part of what makes this condition tricky. Your dog might seem a little off for weeks before things get obviously serious. Watch for:
- A chronic cough that doesn’t improve with antibiotics
- Difficulty breathing or labored, rapid breathing
- Fever that comes and goes
- Unexplained weight loss
- Lethargy and low energy
- Poor appetite
- Eye changes, like cloudiness, redness, or discharge (more common with blastomycosis)
- Skin lesions or unusual lumps
- Limping or bone pain (a sign the infection may have spread)
If your dog is showing several of these together and hasn’t responded to standard treatment, that’s a strong signal to push for more thorough testing. Tell your vet exactly where your dog has been, including any travel, hikes, or time spent in areas known for these fungi.
Diagnosis: what to expect at the vet
Getting a definitive diagnosis for a fungal lung infection takes a few steps. Your vet will likely start with a chest X-ray, which can reveal patterns in the lungs that look different from bacterial pneumonia and can suggest a fungal cause. From there, the workup usually includes:
- Fungal titer tests: Blood tests that detect antibodies (the immune system’s response proteins) to specific fungi, helping identify which organism is involved
- Urine antigen tests: Especially useful for blastomycosis and histoplasmosis, these look for pieces of the fungus itself in urine
- Cytology or biopsy: A sample from a lymph node, skin lesion, or lung tissue is examined under a microscope to confirm the fungus is present
- Bronchoalveolar lavage: A procedure where fluid is flushed into the airways and collected, then analyzed, to look directly for fungal organisms in the lungs
This process takes time and, in some cases, multiple tests. It’s not a quick answer, but the specificity matters because different fungi respond to different treatments.
Treatment and prognosis
Treatment for fungal pneumonia in dogs almost always means a long course of antifungal medication. We’re not talking two weeks, we’re talking months. Your vet may recommend:
- Itraconazole: An oral antifungal that’s commonly used for blastomycosis and histoplasmosis, typically given for six months or longer
- Fluconazole: Another oral antifungal, often preferred for Valley Fever and cases where the infection has spread to the nervous system or eyes
- Amphotericin B: An intravenous (IV) antifungal used in severe or life-threatening cases; it’s more powerful but also harder on the kidneys, so it’s usually reserved for dogs that are critically ill
Prognosis depends heavily on how early the infection is caught, how far it has spread, and how your dog responds to medication. Dogs diagnosed before the infection becomes widespread generally do well. Severe cases, or those where the infection has reached the brain or eyes, carry a more guarded outlook. Regular recheck appointments and repeat testing are part of the process, so your vet can confirm the treatment is working before stopping the medication.
Where your dog lives and plays matters: a geographic and activity risk guide
Fungal pneumonia isn’t random. The risk depends heavily on where your dog spends time and what they do outdoors. Knowing what lives in the soil in your area can help you act faster if something seems off.
Where these fungi live
| Fungus | Condition | Where it’s found |
|---|---|---|
| Coccidioides | Valley Fever | Desert Southwest: Arizona, California’s Central Valley, New Mexico, Nevada, and parts of Texas. Dry, dusty, arid soil. |
| Blastomyces | Blastomycosis | Ohio and Mississippi River valleys, Great Lakes region, parts of the Southeast. Moist, sandy, or wooded riverbank soil. |
| Histoplasma | Histoplasmosis | Ohio and Mississippi River valleys, and anywhere with heavy bird or bat populations. Old barns, chicken coops, and areas under bat colonies. |
Outdoor behaviors that raise risk
Some activities put dogs in closer contact with contaminated soil than others:
- Digging in soil, especially disturbed or dusty ground
- Heavy sniffing of soil surfaces or debris
- Swimming or playing along riverbanks and lakeshores
- Spending time near bird roosts, bat-heavy structures, or old farm buildings
- Hiking in endemic regions during dry, windy conditions when spores are more easily airborne
If you live in or near a high-risk region
Tell your vet your location and your dog’s outdoor habits upfront, especially if your dog gets sick and doesn’t respond to antibiotics. Ask specifically about fungal testing if your dog has a chronic cough, unexplained weight loss, or fever and you live in or have recently visited an endemic area. Don’t wait for multiple failed antibiotic courses. Geographic context is a legitimate reason to test sooner. Keeping notes on where your dog has been, including camping trips, travel, or new outdoor environments, gives your vet useful context and can speed up the path to the right diagnosis.
Does pet insurance cover fungal pneumonia?
Yes, Lemonade Pet insurance can help cover eligible diagnostics and treatment for illnesses like fungal pneumonia, as long as your dog is enrolled before signs appear and the condition isn’t pre-existing.
The earlier you get a policy in place, the better positioned you are if something unexpected comes up. If your dog loves the outdoors, lives in or near an endemic region, or you just want to be ready, getting a quote now takes a few minutes and could make a real difference later.
Before we go
Fungal pneumonia takes time to diagnose and even longer to treat, but dogs who get the right care do well. If your dog has a cough that won’t quit, has been somewhere in an endemic region, or hasn’t responded to antibiotics, push for fungal testing sooner rather than later. Early diagnosis is the single biggest factor in a good outcome.
Frequently Asked Questions
Is fungal pneumonia in dogs contagious to other dogs or humans?
No. Fungal pneumonia is not contagious between dogs, or from dogs to people. Each case comes from direct exposure to fungal spores in the environment, not from contact with an infected animal.
How long does treatment for fungal pneumonia in dogs take?
Most dogs need antifungal medication for at least six months, and some cases require treatment for a year or longer. Your vet will use follow-up testing to decide when it’s safe to stop.
What's the difference between blastomycosis, histoplasmosis, and Valley Fever?
They’re three different fungal infections caused by three different fungi, each tied to specific geographic regions. Blastomyces and Histoplasma are most common in the Ohio and Mississippi River valleys, while Coccidioides (Valley Fever) is endemic to the desert Southwest.
Can a dog recover fully from fungal pneumonia?
Many dogs do recover, especially when the infection is caught before it spreads beyond the lungs. Dogs with more advanced disease, or infection that has reached the eyes, bones, or nervous system, have a more uncertain outlook, but treatment can still make a significant difference.
Does Lemonade Pet insurance cover fungal pneumonia treatment?
Lemonade Pet insurance can cover eligible treatment for illnesses like fungal pneumonia, as long as the condition isn’t pre-existing and your dog was enrolled before symptoms appeared. Check your policy details or reach out to Lemonade directly for specifics.
A few quick words, because we <3 our lawyers: This post is general in nature, and any statement in it doesn’t alter the terms, conditions, exclusions, or limitations of the policies issued, which differ according to your state of residence. You’re encouraged to discuss your specific circumstances with your own professional advisors. The purpose of this post is merely to provide you with info and insights you can use to make such discussions more productive! Naturally, all comments by, or references to, third parties represent their own views, and Lemonade assumes no responsibility for them. Coverage may not be available in all states. Please note that statements about coverages, policy management, claims processes, Giveback, and customer support apply to policies underwritten by Lemonade Insurance Company or Metromile Insurance Company, a Lemonade company, sold by Lemonade Insurance Agency, LLC. The statements do not apply to policies underwritten by other carriers.