By Dr. Becker
Most pet owners have heard the term yeast infection, but many don't know exactly what causes it. Sometimes a dog's family assumes their pet is just meant to have a bit of a stinky doggy smell, when in reality he has a problem with yeast overgrowth.
Yeast is a spore-like type of fungi that reproduces through a process called budding. Budding just means that portions of the organism's cell body break off and form whole new yeast organisms.
Yeast infections of the skin and ears are very common in dogs, and are caused by an organism called Malassezia pachydermatis. A normal amount of yeast becomes an infection when the organism begins reproducing uncontrollably. When the yeast reproduction gets out of control, the organisms invade and colonize areas of the dog's body and skin beyond those where they normally live, and in higher numbers.
Yeast are opportunistic organisms. They flourish when the body isn't healthy or in perfect balance.
Dogs Most at Risk for Yeast Infections
Most dogs with yeast infections have immune system imbalances that inhibit the body's ability to control the yeast overgrowth. Yeast infections often occur during or after antibiotic therapy because the drugs have reduced the beneficial bacterial levels necessary to maintain healthy skin defenses.
Yeast can also be a significant problem for pets that are immunosuppressed. This would include pets born immunoglobulin deficient. There are also certain drugs, like steroids and chemotherapeutic agents, which suppress an animal's immune system and can open the door to yeast infections.
I also see lots of yeast infections associated with allergies. An allergy is an immune system over-reaction, and many veterinarians use immunosuppressive steroids like prednisone, dexamethasone, and cortisone to mute or turn off the immune response, making it incapable of managing normal flora levels. This can lead to yeast overgrowth.
Pets with allergies that progress to secondary bacterial skin infections are typically given antibiotics. But antibiotics destroy all bacteria – the bad and the good – which can lead to yeast overgrowth. The more antibiotics given, the worse the yeast infection tends to be. Allergic dogs can also develop allergies to their own yeast, making the problem even worse.
Allergy testing will sometimes show that a dog is having an allergic response to her own natural flora, in which case things can get very complicated. Pets with an underactive immune system (identified by immunoglobulin A (IgA), immunoglobulin M (IgM), and immunoglobulin G (IgG) testing), as well as pets with overactive immune systems and allergies, are both at risk for chronic yeast infections.
Symptoms and Signs of a Yeast Infection
A yeast infection can occur anywhere on a dog's skin, including between the toes, in the armpits, and in deep skin wrinkles and folds. But the most common location for a yeast infection is your dog's ears.
At a minimum, a dog with a yeast infection feels uncomfortable. The discomfort can range from mild to terrible. Almost all dogs with a yeast problem become extremely and chronically itchy at the site of the infection. If it's a problem with her paws, she won't be able to leave them alone. The same goes for her ears. A lot of butt scooting can also be a clue. The terrible itching leads to desperate scratching and chewing, which can result in significant self-induced trauma and pain.
Another thing most pet guardians notice is the smell. Yeast has a very distinctive odor, which has been described as similar to moldy bread, or cheese popcorn, or corn chips. In fact, some people refer to a yeast infection on a dog's paws as Frito Feet. It's a pungent, musty, unpleasant smell that at times can be overpowering.
I'm sensitive to the smell of yeast, so when a patient enters my exam room, the owner may not know her dog has a yeast problem, but I know it as soon as they come through the door. Many dogs have had a yeast problem for so long their owners don't realize their pet is stinky. I've had dog parents say, "I thought she was supposed to smell like that," because they have grown accustomed to their dog's chronic yeast problem.
Other signs of a yeast infection include areas of skin irritation, redness, and inflammation, especially in and around the ears, around the toes and pads of the feet, in nasal, facial or other skin folds, around the anus, under the armpits, on the neck, and sometimes around the tail base. There might also be hair loss, scaly or oily skin, or a greasy hair coat.
Sometimes in chronic, severe yeast infections there are raised scaly patches of skin or the skin darkens and thickens. There might also be a secondary bacterial infection or a foul-smelling yellow-green discharge from the ears. There can also be behavior changes caused by the itching and pain, including depression, loss of appetite, anxiety, and even aggression.
I've seen dogs so intensely itchy that when I try to stop them from digging at their skin, they become aggressive because their discomfort is so overwhelming. It's a very sad situation.
Diagnosing a Yeast Infection
Definitive diagnosis of a yeast infection is accomplished either by cytology (looking at a skin swab under a microscope) or by culturing (submitting a sterile swab of the skin to the lab where the cells are grown and identified on a petri dish).
If there's an ear infection, either diagnosed or suspected, it's extremely important to know whether the eardrums are still intact before putting any liquids, gels, cleansers, or other medications down in the ears. If one or both eardrums have ruptured, putting products into the ear canals can damage the middle and inner ear.
Most dogs with a yeast infection have it in more than one spot. For example, they can have it on all four paws, both ears, or in some cases, over their entire body.
Treating Your Dog's Yeast Infection: Addressing the Diet
Hands down, the most important aspect of addressing chronic yeast is through diet. The simple fact is that we can't treat a moderate to severe yeast infection naturally without addressing your dog's diet. Regardless of the root cause of the yeast infection, nutrition is the most important and first step in treating it.
The nutrition your dog receives either supports his immune system to keep yeast growth under control, or it does the opposite and exacerbates a yeast overgrowth situation. For dogs with yeast, I recommend an anti-yeast diet, which is also called an anti-inflammatory or species-appropriate diet.
Yeast uses sugar as a source of energy. We know that carbs break down into sugar, so the first thing yeasty patients (human or canine) need to do is remove sugar from the diet. And remember that dietary sugar isn't just the white stuff -- it's also honey and high-fructose corn syrup listed on the ingredients panel. Even white and sweet potatoes can feed a yeast problem, along with the tapioca found in grain-free dry foods.
I recommend an entirely grain-free and carb-free diet for patients who have yeast. This step is extremely important. It's impossible to effectively deal with a yeast problem without addressing your pet's diet, regardless of how many supplements or baths you give him. Your dog's nutrition should help keep his normal flora levels balanced.
I also recommend adding a few natural, antifungal foods to the diet, for example, small amounts of fresh garlic, thyme, parsley, and oregano to help reduce the level of yeast naturally. Adding fermented veggies, if your dog will eat them, can also be very beneficial. Raw, unfiltered apple cider vinegar and coconut oil have natural antifungal properties and can be added directly to your dog's meals.
Disinfection Protocol for Yeasty Ears
At the same time we're addressing the diet, we also need to begin a disinfection protocol to treat the areas of the body where the yeast infection is occurring. Yeast love a moist environment, which is why it grows in crevices, including between your dog's toe pads, in the armpit, in the creases of his groin, and around the base of his tail.
It's not enough to just apply a cream, salve, or antifungal solution to affected areas of the body -- those areas must be regularly disinfected. I recommend at least once a day, so that the topical remedies you apply after you've cleaned the area have a chance to work. Applying any topical agent without removing the dead yeast first can actually make the problem much worse.
If your dog's ears are the problem, you'll need to disinfect them daily with either a store-bought solution or witch hazel (which is what I use), and really large cotton balls. Use as many cotton balls as it takes to remove all the debris from the ears at each cleaning. I don't recommend putting Q-tips down the canals of your dog's ears, but you can use Q-tips around the outside to remove the yellowish stinky goo on a daily basis.
Keep in mind some dogs just naturally produce a lot of gunk in their ears and that natural debris or wax needs to be removed every day to avoid yeast and other types of ear infections.
The question is, "How often should I clean my dog's ears?" The answer is, as often as you need to, to keep the ear canals clean and dry. The amount of cleaning depends on the amount of debris that accumulates in the ears. If your dog produces goo on a weekly basis, clean your dog's ears weekly. But if you look in your dog's ears and you can see wax or debris on a daily basis, clean your dog's ears every day. By keeping your dog's ears clean and dry, you can actually prevent yeast infections, and if a yeast infection is present, you can prevent it from progressing to a full-blown bacterial infection.
Disinfecting Yeasty Feet
If the yeast overgrowth is on your dog's feet, keeping them clean is essential, and that means dunking them rather than spraying or wiping them down. Yeast grows under the nail beds and in the creases of your dog's feet, which is why the paws must be submerged in a foot soak rather than just wiped off.
Depending on the size of your dog, you can fashion a foot soak from almost anything that holds water. If your pet is small, you can simply stand her in the bathroom or kitchen sink. For bigger dogs, you can use a plastic sweater box with water from the hose, or a coffee can or cup filled with water. You want to be able to dunk each foot and then pat them dry.
I recommend a gallon of water, a cup of hydrogen peroxide, and 1-4 cups of white vinegar as a foot soak solution. You can use this solution as many times a day as necessary to keep your dog's feet clean and effectively reduce itching. There's no need to rinse if you use this solution – just pat the paws dry.
Leaving the solution dried on your dog's paws provides an antifungal effect, and can also reduce licking and chewing on the paws. Remember that hydrogen peroxide can lighten your dog's fur, so keep that in mind.
Natural Antifungal Baths and Rinses
For skin yeast infections, I recommend a natural antifungal shampoo. I typically use tea tree oil or an herbal blend. You can bathe your dog as often as necessary, but once a week at a minimum. Since grains and carbs feed yeast, I don't recommend using oatmeal-based shampoos for pets with allergies or yeast infections.
The good news is that I have managed many, many patients with yeast and terrible itching solely with dietary adjustments and two to three weekly baths. I realize baths can be an annoying, frustrating thing to deal with for both you and your pet. They take time, but they are actually a cheap and very effective way to manage yeast and keep your pet feeling comfortable. It's also a safe non-toxic treatment compared to the antifungal drugs that conventional veterinarians typically prescribe.
I also like antifungal rinses and sprays in between disinfecting baths. A rinse is poured on your dog after a bath and may help extend the number of days in between baths to control yeast.
There are several different rinses you can try. I've had success with vinegar, lemon juice, and essential oils. Vinegar and lemon are astringents, so they are naturally drying. They are excellent for dogs with greasy or oily coats. Just add one cup of vinegar or one cup of lemon juice -- or 10 drops of peppermint oil with 10 drops of lavender oil -- to a gallon of water. Since lemon juice can also lighten fur, I usually recommend vinegar or the essential oil mixes for dogs with dark coats.
After shampooing your dog and rinsing thoroughly, follow up with your gallon of natural antifungal rinse to knock down the amount of yeast remaining on the skin. Pour the rinse solution over your dog's collar, from her neck to the base of her tail, making sure not to apply it to her head. Rub the solution into her coat and skin, focusing on the areas where she is yeasty. Make sure that you get the solution around the armpits, down around the feet, into the groin area, and around the tail base. Don't rinse the solution off -- just pour it on, rub it in, and then towel dry.
You can also put the rinse solution into a spray bottle and mist your dog's itchy areas throughout theday as needed to help control itching and yeast overgrowth. Adding a dropper full of colloidal silver to the spray bottle also adds an additional all-natural antimicrobial agent.
If your dog only has yeast issues in the warmer months of the year, spring and summer are the times when you'll need to be really focused and vigilant about disinfecting him and making sure his diet is not contributing to a yeast overgrowth problem.
It's important to remember these suggestions aren't magic. It will take some time on any all-natural protocol to see improvement. If these easy, cheap solutions are effective at managing your dog's chronic yeast issues, I'd recommend you continue the carb-free, preferably fresh food diet, year-round to minimize your pet's likelihood of fostering future opportunistic yeast infections.
Beneficial Supplements and Additional Testing
There are certain supplements your holistic veterinarian may also recommend to assist in re-establishing healthy and normal levels of yeast in your pet's body. Probiotics can be very beneficial, as well as the herbs pau d'arco, goldenseal, caprylic acid, or the more potent 10-undecenoic acid, which are organic unsaturated fatty acids many holistic veterinarians prescribe for stubborn yeast infections.
Unfortunately, some dogs have year-round yeast problems. No matter what food they're eating, and what remedies their owners are using to manage their condition, the yeast is just out of control. In these cases the root cause is most likely an immune system issue.
When I have patients with stubborn yeast infections that will not go away, I do blood tests to measure immunoglobulin levels (IgG, IgM, and IgA). Generally these levels are low in a dog with constant yeast overgrowth. If your dog is producing healthy levels of immunoglobulins, he should be able to overcome almost any infection and particularly an opportunistic yeast infection.