The Dangers and Risks of Mold Exposure for Dogs

The International Center for Toxicology and Medicine estimated that 70% of all houses in the US have a mold problem. Like most people, you have read about the effects of mold in human beings - pulmonary distress, wheezing, coughing, headaches, and, in a worst-case scenario, pneumonia and bronchitis.

But did you know dogs could be in much worse danger of mold exposure than humans? The dangers of mold to pets only came to light in 2007 when two cats died of pulmonary hemorrhage during a simple dental procedure. It was discovered that the cats were living in a home that was heavily contaminated with mold. According to the report, pulmonary hemorrhage is just one of the significant risks of mold contamination in pets.

Most homes have the perfect environment for mold growth because the fungus doesn’t require much. It could be a pinhole leak in the pipes, moisture vapor in the bathroom, water pooling in your attic, or even a malfunctioning AC.

Pets, including dogs, get mold contamination in two ways:

  1. 1
    Ingestion. The dog can eat spoiled food leftover from the previous day. Some food types such as milk and meat contain mold that can release poisonous mycotoxins. Some symptoms of mold ingestion include vomiting, loss of appetite, and change in stool.
  2. 2
    Inhalation. The dog can either directly inhale the mold in spoiled food or soil or indirectly from a mold-contaminated environment like the basement.

Luckily, your furry friend doesn't have to end up like those poor cats. If you pay attention to your dog, you will notice some initial signs of mold exposure early enough.

Symptoms of Mold Exposure

Dog standing on moldy floor
  • Respiratory issues like wheezing, coughing, difficult breathing.
  • Excessive scratching and chewing themselves to the extent of losing hair and bleeding.
  • Excessive licking.
  • Lethargy.
  • Fever.
  • Runny nose.
  • Loss of appetite and weight loss.
  • Gastrointestinal issues like diarrhea.
  • Pulmonary hemorrhage and bleeding from the nose after prolonged exposure to mold.

Blastomyces Dermatitidis Disease

Blastomyces dermatitidis is a type of mold that mostly affects dogs and humans. The mold is commonly found in moist soil and gets into your body through inhaling. Once the mold is inside the body, it migrates to the lungs and germinates into yeast.

Most dogs will fight off the infection easily unless they inhaled a considerable population of the dangerous mold. In such instances, the yeast will cause pneumonia and eventually spread to skin, bones, eyes, and testes. Without treatment, the dog will be in extreme pain and eventually die.

While Blastomyces dermatitidis is treatable if caught in good time, it's hard to pinpoint exactly where the dog got it from. If your dog goes outside to hunt or the park, they could inhale mold in moist soil anywhere out there.


One of the less known facts about long-term mold exposure in dogs is aspergillosis. This opportunistic fungal infection occurs because mold compromises the dog’s immunity and leaves it weak. Aspergillosis can occur in the dog’s nasal passage or throughout the body.

Signs of aspergillosis include:

  • Nasal pain and discharge.
  • Bleeding from the nose.
  • Low appetite.
  • Fever and vomiting.
  • Spinal Pain, bone inflammation and weight loss when the infection has affected the entire body.

Prevention is the Best Cure

Cleaning dog dish to prevent mold

Most of the symptoms associated with mold in dogs are also common in other illnesses like the cold. This means your dog could be inhaling mold every day for a while before you realize what is causing the physical distress.

The most effective way to protect dogs is to prevent mold growth and remove any existing mold as soon as you see it.

  1. 1
    Clean and dry the dog’s bowl every day before adding fresh food.
  2. 2
    Store pet’s food in a clean and dry place, preferably a sealed container to prevent mold.
  3. 3
    Regularly check the underside of hidden and dark areas such as wallpaper, drywall, carpeting, wall corners, and attic.
  4. 4
    Keep your home airy by getting rid of clutter and opening windows and doors so air can get in. You must also keep the AC well serviced to ensure its working well.
  5. 5
    Keep your home airy by getting rid of clutter and opening windows and doors so air can get in. You must also keep the AC well serviced to ensure its working well.
  6. 6
     Repair a leak as soon as it happens no matter how small.
  7. 7
    Call professionals to take care of the cleanup in case of a flood.
  8. 8
    Clean the dog's cage, litter box, and accessories regularly.
  9. 9
    Keep the dog away from moldy environments such as trash cans, swampy areas, riverbanks, flooded areas, crawl spaces, and basement.

Treatment of Mold Exposure

Dog getting treated for mold exposure

If you have reason to suspect your best friend has been exposed to mold, you should rush them to a local veterinarian. For instance, you may notice the dog is looking sick, tired, and losing hair a few weeks or months after a flood in your home or water damage.

Besides listening to your side of the story, the vet can also conduct a test to know if mold exposure is actually the cause of the illness. He may then prescribe detoxifying drugs, antibiotics, and steroids, depending on the situation.

Most dogs recover quite well after treatment, but follow up blood tests to monitor liver function are required. If the pup is too sick, you might have to leave them at the doctor's office until they are well.

Getting Rid of Mold

A sick dog is a sure sign that your home is under mold attack unless the dog goes outside the perimeter. If you have seen the mold and it's not significant, use some water, vinegar, and baking soda to clean up that mess quickly.

On top of the prevention measures we highlighted before, identify problem areas in your house and dry them out. Ensure you keep moisture out by having proper ventilation and letting the sun in as much as you can. When cleaning, use mold-resistance products, and keep checking how humid your house is. Ensure you directing water away from your home, including sprinkler water.

Remember, signs and symptoms of mold exposure often resemble other health conditions so let a vet determine if it’s mold affecting your pooch. Educating yourself on your region’s climate will help you prevent moisture since there is no one size fit all.


  1. Ward, J., & Leduc, C. (2020, May 15). Blastomyces Dermatitidis. Bust Mold.
  2. CORRECTING MOLD MISINFORMATION. (2015). Wilsonweb.Physics.Harvard.Edu.
  3. Mader, D. R. (2007, September 1). Acute pulmonary hemorrhage during isoflurane anesthesia in two cats exposed to toxic black mold (Stachybotrys chartarum). PubMed.

About the Author: John Ward is an account executive at Mold Busters, specializing in indoor air quality issues of the most delicate nature. Over the years, he has completed hundreds of mold remediation jobs and thousands of air quality tests for homeowners and businesses across Ontario and Quebec.

Click Here to Leave a Comment Below 0 comments