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We and our pets can be susceptible to all sorts of different infections, caused by bacteria, viruses, fungus, or single-celled organisms called protozoa.
But did you know that yeast is one of the most common culprits when it comes to causing infections in all kinds of pets, including dogs, cats, rabbits, guinea pigs, and birds?
Yeast – Little Buggers, Big Problems
Yeast are a spore-like form of fungus. They happily hang out on most normal skin surfaces, especially between your pet’s toes, inside his ears, under his tail and armpits, and on his face and abdomen. Yeast can also be found in the mouth, nose, and gastrointestinal tract. Most of the time the body maintains a normal population of both yeast and bacteria, and neither cause a problem because they are kept in check by the immune system. But sometimes changes in the body can cause yeast to overgrow, leading to opportunistic infection.
These changes usually happen due to an increase in skin oils (which occurs during allergic flare-ups, or with the skin disease seborrhea), hormone imbalances, a deficiency in the body’s immune system, or if the pet already has a bacterial infection.
Pets with lots of skin folds, such as Pugs, Bulldogs, Shar-peis, and Persian cats are at an increased risk of developing yeast infections of the skin, while some cats and dogs can develop an overgrowth of yeast in the mouth and throat, commonly known as “thrush”.
Yeast infections can cause intensely itchy, inflamed, thickened, crusty skin with a bad odor. They can also cause body-wide systemic infections that can be very serious for pets with compromised immune systems (such as cats with FeLV or FIV).
The Culprits – 2 Different Types of Yeast
There are two major types of yeast that cause infections in our pets:
1. Malassezia
Malassezia pachydermatis live on the skin’s surface. Overgrowths happen when the skin becomes damaged, or if the body’s immune system becomes weakened. This can occur in pets with the following conditions:
- Allergies (either to fleas, certain types of food, or inhalants like pollen or mold)
- Seborrhea
- Mange
- Endocrine disorders (such as Cushing’s disease or hyperthyroidism)
- Autoimmune skin diseases, where the body’s immune system attacks its own skin by mistake
- Pets who are on long-term use of steroids, which suppress the immune system
Malassezia thrives in a warm, moist, humid environment, so it can cause nasty ear infections in dogs with long, floppy ears that don’t allow sufficient airflow through the ear canal. It can also infect the ears of cats who are already suffering from an infestation of ear mites. Dogs and cats with yeast infections in the ear usually have a black, brown, or yellowish waxy, bad-smelling discharge. They may shake or tilt their heads, and scratch constantly at their ears.
Ear infections must be treated promptly, since they can cause the eardrum to rupture. They can also progress to the inner ear and cause loss of balance, paralysis of the muscles in the face, walking in circles, or permanent head tilting.
Skin infections caused by Malassezia are not contagious, either to humans or to other pets.
2. Candida
Candida albicans is a sugar-digesting yeast normally found in a pet’s mouth, digestive system, ears, and nose. Candida infection can occur in one specific part of the body (localized), or it can spread throughout the entire body (systemic). Either types of infection can cause extreme discomfort.
Pets at risk for developing candida infection include:
- Cats with compromised immune systems, such as those with Feline Leukemia Virus (FeLV) and Feline Immunodeficiency Virus (FIV).
- Dogs with allergies, skin trauma, burns, or parvovirus.
- Any pet with diabetes, due to fluctuating blood sugar levels.
- Rabbits and Guinea pigs who are stressed or have other bacterial infections.
- Birds (especially cockatiels) who are malnourished, or have experienced stress or smoke inhalation.
- Any pet who has to have a urinary catheter in place for any length of time.
Symptoms of candida infection will depend on what part of the body is affected. Candida overgrowth in the mouth and throat causes drooling, while candida in the bladder can cause cystitis (inflammation of the bladder). Candida can also infect the ear, causing the same symptoms as Malassezia.
Diagnosing Yeast Infection
If your veterinarian suspects a Malassezia infection, he or she can perform any one of the following tests:
- Skin scraping: a scalpel blade is used to scrape the skin to collect yeast organisms.
- Impression smear: a microscope slide is pressed directly against the skin, and any yeast present will stick to the slide.
- Cotton swab sample: a moistened cotton swab is rubbed on the skin or in the ear canal to collect yeast.
- Acetate tape preparation: a piece of clear tape is applied to the skin; yeast will stick to the tape.
- Skin biopsy: a small piece of skin is obtained using a tool called a biopsy punch. This is the most invasive test, but will indicate if the yeast has penetrated the surrounding tissues.
Samples are then viewed under a microscope to determine if yeast is present.
If your veterinarian suspects a Candida infection, he or she can:
- Take a urine sample, and examine the urine under a microscope for the presence of yeast clumps.
- Use a sterile swab to collect a sample, and send the swab to the lab for a fungal culture. The swab is then smeared across a small round plate containing a nutrient-rich gel. Any yeast present will begin to grow and can easily be seen on the surface of the plate.
- Perform a skin biopsy (see above).
Treating Yeast Infections
Yeast infections are treated topically, orally, or by using a combination of both.
1. Topical Treatments
For skin infections, medicated shampoos containing benzoyl peroxide, chlorhexidine, and the antifungal medications miconazole or ketoconazole are very effective. These shampoos need to be left on the skin for at least 10 minutes before they are rinsed off. Treatments must be done every 3-5 days for a period of two to twelve weeks.
For small individual lesions, some veterinarians recommend using a mixture of acetic acid (white vinegar) and water applied directly to the affected spots. A topical antifungal ointment may also be prescribed. Antifungal medications are also available in lotion, spray, and wipe forms.
For yeast infections in the ears, one of the most commonly prescribed medications is Tresaderm®. This medication combines thiabendazole (a drug that controls fungus, parasites, and bacteria), neomycin (an antibiotic to kill bacteria), and dexamethasone (a steroid to help reduce itching and inflammation). Other antifungal ear medications such as miconazole or clotrimazole may also be used.
2. Oral Treatments
For severe or recurring cases of yeast infections of the skin, veterinarians usually prescribe oral antifungal medications such as ketoconazole, itraconazole, or fluconazole. These medications are very effective, but they often need to be given for several months to clear the infection. They can also be somewhat hard on the liver, so additional blood tests may be needed to make sure the liver is functioning normally during treatment.
Pets with yeast dermatitis often have a simultaneous bacterial infection, so oral antibiotics are also given for about 4-12 weeks to kill the bacteria. Benadryl may also be used to help with severe itching.
If a veterinarian suspects the yeast infection was caused by a food allergy, the recommendation may be to change the pet to a hypoallergenic diet.
Are Some Breeds of Dogs More at Risk?
Certain dog breeds are thought to be genetically predisposed to developing yeast infections. These include:
- Australian terrier
- Basset hound
- Chihuahua
- Cocker spaniel
- Dachshund
- Lhasa apso
- Maltese
- Poodle
- Shetland sheepdog
- Silky terrier
- West Highland White terrier
However, any dog can develop a yeast infection.
Yeast, Yeast Go Away
Yeast infections can be quite aggravating. Tricky to diagnose, they’re easily confused with other types of skin conditions. They’re also difficult to treat, as treatment needs to be continued for long periods of time and there’s no guarantee that the infection won’t come back.
Regardless, yeast infections need to be treated immediately to get them under control. Without treatment, yeast will continue to spread, causing intense discomfort and sometimes permanent damage to skin, ears, or other organs.
It’s not unusual for some dogs with severe allergies to have yeast and/or bacterial infections several times a year. If this happens to your dog, your veterinarian can work with you to develop a treatment plan to help you best manage his condition.
Have you ever treated a pet for a yeast infection? Please tell us about it in the comments below!
1 Photo Credit: Veterinary Practice News
2 Photo Credit: wikipedia
3 Photo Credit: Creative Commons License
4 Photo Credit: Creative Commons License
Great article Camille! Haley suffered with yeast ear infections for years and was treated on and off with Tresaderm. It wasn’t until we switched vets that she was treated with a type of thick waxy medication that stayed in place inside the ear and treated the infection for a week or two, that she was finally cured. I can’t recall off hand what the name of that medication was but we were so thrilled to finally have it treated properly.
Thank you, glad you enjoyed it! Poor Haley…those yeast infections can be so aggravating. 🙁 We had several patients that needed treatment on and off for years too. I always felt so bad for those dogs, since the itching was terrible. I’m glad you found a medication that worked for her! If you ever recall the name of it, can you please let me know? I’m curious to know what it was!
I just checked Haley’s billing record for that treatment and it only says “Infused Ears”. Usually they list the medication name, so I’ll have to ask the next time we go in for an appointment. It was a thick, waxy type substance that completely filled the ear canals and it’s purpose was to keep the medication in place for about two weeks.
Perhaps it’s just a different way of applying the typical antifungal/antibiotics? I’m curious now too. It worked really well for Haley though.
I am now so curious as to what they used…we used to use Tresaderm and Panalog. The Panalog was a pretty thin ointment, so it definitely wasn’t thick (it used to leak out a bit whenever the dogs shook their heads). I always wished we had something that would stay in contact with the ear canal and stay put without getting flung all over. Whoever developed the method they used for Haley is probably well-loved by veterinary professionals everywhere! 🙂 If you find out the name, please do let me know… thanks so much!
My pit has serious problems yeast. She had hematomanoma surgery…which now one of her ears flop ( not happy) she had beautiful ears that stood straight up anyway she prescribed..ear wash once a week and the next day once a week she prescribed OTOMAX ointment for yeast matinance…
I have a white shepherd dog whose had ear infections on and off his whole life. Then one day he started scratching all over, developed a brittle, dull, oily coat and was chewing at his feet and elbows. We put him on a hypoallergenic diet and spent 6months of him scratching and crying or being on cortisone. Finally in desperation I started making home cooked meals and then moved him onto Acana and we’ve never looked back. He still gets the occasional ear infection but nothing like before, and it’s been 2 years since I changed his food. He has become much more out going than before and keeps coming for cuddles which he never used to like.
I’m so glad to hear your dog is feeling much better! This is a perfect example of the importance of exploring different options when it comes to what works best for your pet. Like people, every pet’s body is different, so treatment options that work for some may not work for others…. so it’s critical to keep trying until you find what your pet responds best to. It’s great that you didn’t give up and were able to find a food that he is flourishing on!
And as you point out, when they feel better, their personalities can really blossom. 🙂 Thank you so much for sharing!
My cat has a yeast infection in his ears. The vet confirmed it. The ear drops prescribed were just for 10 days. Will the yeast come back?
Hi JJ, sorry to hear about your kitty’s ear infection! The quick answer to your question is that the yeast infection COULD come back, but that doesn’t mean it will. Yeast is always present on the skin of cats (it’s part of the natural flora), but if anything changes the body’s balance (such as moisture in the ear, food allergies, or hormonal imbalances), it can overgrow and cause an infection. The medication you were given is most likely an antifungal, so it will suppress the yeast overgrowth so the balance between yeast and bacteria can return to normal.
To prevent a recurrence, try keep your cat’s ears as clean and dry as possible. You can periodically check his ears and use a dry cotton ball just inside the ear to remove any moisture or visible wax. (However, avoid overcleaning his ears, since that can cause irritation that can lead to another infection; and never insert anything down into his ear canal.) Keeping a close eye on his ears will help you know if an infection is starting again.
If is current infection is not gone in 10 days, ask your vet if you can continue the medication for awhile longer. Once the infection clears up, if it comes back again, talk with your vet about other potential causes, such as food allergies or a weak immune system. Hope this helps, and good luck!
My cat had black yeast in her ears. Dr put some type of medicine that was like a thick plug in her ears and it stayed there and melted over a week’s time. Its now gone. He also switched her to Royal Canin Hydrolyzed Protein food. Said the yeast was from her food. It hasn’t come back; but, this vet food is expensive.Wish I could find something else.
Yes, food allergies can definitely play a part in yeast overgrowing and causing an infection. I’m glad to hear your kitty is feeling better! You may want to check back with your vet to see if there are any other foods out there that he recommends that will accomplish the same purpose, as some brands are more expensive than others.
I discovered this while researching for my female shih tzu. I noticed a stinky almost smell feet smell (the type where it is almost cheesy in a bad way) And next thing I notice is under her armpit there is dark colored paste on her skin and fur. Could this be a yeast infection? I would take her to the vet but currently we are struggling financially due to a recent emergency.
Hi Char, this could be a yeast infection, but it could also be a bacterial skin infection (or both). If you’re not able to get to the vet right away, and it’s not too painful for your dog, the one thing you can do to help your dog at home is to use clippers to shave the hair off the spot (to better expose the skin), then use a mixture of white vinegar mixed with a little water applied directly to the spot several times a day. There are also medicated shampoos you can buy that contain benzoyl peroxide, chlorhexidine (an antiseptic to kill bacteria), and the medications miconazole or ketoconazole (which kill yeast). You can buy these shampoos without needing a prescription from your vet, but keep in mind if the spot gets bigger or doesn’t seem to be healing, or becomes painful for your dog, she should be seen by a vet so the infection doesn’t continue to spread. I hope this helps and that your little girl is feeling better soon!
My small dog started losing his hair and he itches a lot he also has an order I’ve try everything but I can’t get his hair to go back you have any ideas what I can do for him