Seeing your dog constantly itch and scratch can be stressful. A musty odor from your dog's ears is also an unpleasant surprise when you're cozy on the couch together!
If your dog has red, irritated ears, paws, or other areas of skin, the cause could be yeast. Yeast infections in dogs are common and treatable, but they need attention from your dog's veterinarian.
What Is a Yeast Infection in Dogs?
Also called yeast dermatitis, dog yeast infections are an overgrowth of the fungus Malassezia pachydermatis (1). While the word "fungus" might remind you of mushrooms or mold, yeast are tiny fungi, invisible without a microscope. Yeast organisms grow on the skin and ears of healthy dogs, humans, and other animals.
What Causes Dog Yeast Infections?
Their scientific name may be wordy, but Malassezia is usually harmless. Yeast are ordinary residents of your dog's skin, along with other fungi and bacteria.
However, underlying health problems can cause an unusual overgrowth of yeast on the skin. Yeast overgrowth means itchy, painful, skin inflammation for your dog. Enzymes released by the yeast can also weaken your dog's skin barrier, causing secondary bacterial infections.
Importantly, yeast infections are not contagious. Your dog did not catch the disease from another dog. There's also no evidence that antibiotics, oatmeal shampoos, or dietary sugars cause yeast overgrowth.
Underlying conditions that can cause yeast infections are:
- A suppressed immune system. Usually, your dog's immune system prevents yeast from growing too rapidly. If the immune system is compromised, yeast infections become more likely. Some dogs have immune deficiencies from birth. Contagious viruses that cause parvo and distemper also kill protective immune cells.
- Increased oil production. Oily skin creates the perfect environment for yeast overgrowth. Dogs with food or environmental allergies are more likely to develop yeast infections. A disease called seborrhea can also cause oily skin.
- Certain medications. Some drugs, like corticosteroids (steroids), suppress your dog's immune system as a side effect. While these therapies are necessary to treat a disease, they can make your dog's skin vulnerable to yeast infections. Your veterinarian will prescribe the lowest possible dose of steroids to reduce the chance of side effects.
- Genetics. It's unlucky, but some dog breeds are naturally at higher risk of developing yeast infections. These breeds include West Highland White Terriers, Boxers, Shih Tzus, American Cocker Spaniels, Basset Hounds, English Setters, Australian Silky Terriers, and Poodles.
Symptoms of Yeast Infections in Dogs
Your dog's yeast infection symptoms will depend on how severe the overgrowth is and which body part is affected. The most common signs of yeast infections in dogs are:
- Moderate to severe itching
- Licking the affected area
- Skin redness and irritation
- A musty, sweet smell in the ears
- Greasy skin or fur
- Loss of hair
- Recurrent ear infections
- Darker patches of skin (hyperpigmentation)
- Thickened patches of skin (epidermal thickening or "elephant skin")
Since yeast are everyday residents on your dog's skin, yeast overgrowth can occur anywhere. Common locations for yeast infections in dogs are:
- Ears. Your dog's ears are easy targets for yeast infections. Overgrowth is more likely in any area with reduced airflow. Check your dog's ears regularly, especially if their ears are dangling or floppy. Signs of an ear yeast infection include head rubbing, a musty or sweet odor, redness, and brown discharge. Ear mites in dogs are distinct from yeast infections and require different treatments.
- Face. Dog breeds with "wrinkly" skin, including "smushed-nose" breeds like Bulldogs, tend to get yeast infections more often. Closely monitor folded skin for redness, irritation, and greasy or flaky spots. Dogs with face infections tend to rub their heads on the ground.
- Paws. Your dog's feet will be irritated, red, and itchy if a yeast infection has developed there. Yeast usually set up shop in the areas between the paw pads. You may notice your dog licking or chewing their paws often.
- Belly. While yeast infections can happen anywhere, the sensitive skin on your dog's stomach is more prone to overgrowth.
Yeast Infections in Dogs and Ear Mites: What's the Difference?
Ear yeast infections can have the same symptoms as dog ear mites (get more information on this here). Both organisms are microscopic, so it's almost impossible to tell the difference by looking. Ear mites are a contagious parasite related to spiders, while yeast infections are not contagious.
Yeast infections and ear mites also require different treatments. The medication for one won't work on the other. Your vet can take a sample to diagnose the cause of your dog's itchy ears.
How Are Yeast Infections Diagnosed?
Take your dog to see their veterinarian if you suspect they may have a yeast infection. Symptoms alone can't confirm this condition, so getting an official diagnosis is critical. Additionally, yeast overgrowth has an underlying cause that needs treatment. Otherwise, the infection will keep coming back!
Fortunately, the tests to diagnose yeast infections in dogs are straightforward. Each involves your veterinarian collecting a sample and studying it under a microscope. The exact method will depend on your dog's symptoms. Techniques your veterinarian might use to diagnose a yeast infection include:
- Pressing a microscope slide against the affected skin (Impression smear)
- Gently scraping the skin with a sterile blade (Skin scraping)
- Rubbing a moist swab on the affected area (Cotton swab sample)
- Placing a clear piece of tape on the skin (Acetate tape preparation)
- Taking a small sample of deeper skin layers (Skin punch biopsy)
Once your vet has a good sample, they'll stain it with dye to make the yeast cells visible. Samples from dogs with severe or repeated yeast infections may need to be sent to a specialist.
How are Yeast Infections in Dogs Treated?
Fortunately, there are multiple ways to treat yeast infections in dogs. The goal of treatment is to reduce the number of yeast organisms. Doing so requires controlling underlying diseases that make yeast overgrowth more likely.
Your veterinarian can determine which yeast infection treatment is appropriate. They'll base their recommendation on symptom severity, affected body part, and other factors. The main categories of treatment for dog yeast infections are:
- Topical ointment. Your vet will likely prescribe an ointment, lotion, or cream if a small part of your dog's body is affected. It's crucial to apply topical treatments regularly; otherwise, yeast will grow back.
- Medicated shampoo. Suppose your dog's yeast infection is more severe or a larger body area is affected. In that case, your veterinarian may recommend a medicated shampoo. These products contain benzoyl peroxide and selenium sulfide, as well as anti-fungals like ketoconazole. Your dog may need multiple medicated baths per week.
- Oral medications. Dogs with severe, widespread, or chronic infections need anti-fungal pills. These medications reach deeper layers of skin than ointments. If your dog has developed a bacterial skin infection (called pyoderma), they will also need antibiotics.
What about popular home remedies for yeast infections in dogs, like coconut oil, oregano oil, probiotics, fermented food, or yogurt? Unfortunately, no studies have indicated that these treatments are effective for yeast overgrowth. Dog foods that claim to be "yeast-free" or "anti-yeast" have not been shown to help either.
Home remedies may not hurt, but each dog's case is unique. Apple cider vinegar for dog yeast infections is an example: the acidic pH of vinegar discourages yeast growth. But, if your dog has already itched their ear raw, applying vinegar will be painful and further damage their skin (2).
What Is the Prognosis for Dog Yeast Infections?
Many cases of yeast overgrowth don't require tri-weekly baths or high-dose prescription medicines. Your buddy will be itching and scratching less within the first week or so of treatment.
Still, remedying your dog's yeast infection may take several months, depending on the situation (3). Consistency and following your vet's instructions are the best ways to help your friend feel better and keep the infection from returning.
Treatment may control rather than cure yeast overgrowth in dogs with allergies or weakened immune systems. Fortunately, managing the primary disease with your veterinarian will make your dog less prone to yeast infections in the future.
Can Yeast Infections in Dogs Be Prevented?
There are multiple ways to reduce the likelihood of a skin yeast infection for your dog. The best way to prevent yeast infections is to keep up with your dog's annual veterinary exams. Your veterinarian will keep your dog's immune-boosting vaccines up to date, and they'll see the first signs of diseases that make yeast infections more likely.
Regular brushing, baths, and ear and face cleaning also help prevent yeast overgrowth. Grooming your dog can be a bonding experience with encouragement and a few healthy treats! If you think your dog may have a yeast infection, see your veterinarian and help your friend feel better as quickly as possible.