Itchy Dog? Don’t Overlook This Potential Cause: Yeast Infection.

Yeast is a normal inhabitant of canine skin, but sometimes this visitor outstays its welcome and causes uncomfortable itching and scratching.

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The vicious cycle of itching, scratching, infection and more scratching can result in yeast infections. Photo: burroblando

Itching isn’t always about allergies or parasites.

One evening, the next patient on my list was a West Highland Terrier named Charles, and like so many Westies, he had a history of itchy allergy problems.

But it was plain to see the dog’s skin was a greasy mess:

  • His armpits and groin were especially bad.
  • The skin had lost its suppleness and was black and thick as rhino hide.
  • And he had a strange odor.

This was more than an allergy.

I just want some more of his anti-itch tablets, the dog’s caregiver grumbled. She was upset at having to pay for a consultation when all she wanted was more of the little white pills that had quelled the itch in the past.

From her crossed arms and hard stare I guessed she wasn’t going to take my next piece of news well. I don’t think his itchiness is caused by the allergy alone,” I said, and suggested a simple test to investigate. Begrudgingly, she agreed.

Pressing a strip of sellotape to the dog’s greasy skin, staining the sample and examining it under the microscope showed I was right to be suspicious. Charles had a heavy yeast infection.

Causes of Yeast Infection in Dogs

Think of this as the doggy equivalent of athlete’s foot.

Yeast, a normal inhabitant on the surface of the skin, start to breed out of control and create an infection. In dogs, the yeast in question is called malasezzia.

Usually malasezzia coexists happily with the dog’s skin and doesn’t cause a problem. But if the skin’s immunity dips, the malassezia breeds and takes advantage.

In other words, it’s a classic vicious circle:

  • An allergy weakens the skin.
  • The yeast breeds.
  • The dog scratches, causing further damage.
  • And the cycle repeats.

Some dog breeds, such as Westies, Basset Hounds and Cocker Spaniels, are more likely to suffer from yeast infections than others, which implies there is a genetic tendency toward poor skin health.

Malasezzia also thrives in a warm, moist environment, which makes skin traumatized by constant licking the perfect paradise.

Factors that can weaken the skin’s ability to keep yeast in check include:

  • Allergies: Where inflammation linked to allergies weakens the skin’s immune system.
  • Seborrhea: Excessive production of grease, which yeast loves.
  • Hereditary factors: Some breeds are more prone to yeast infections than others, including Dachshunds, Cocker Spaniels, Poodles, Basset Hounds and West Highland White Terriers.

Also, be wary of yeast infections if your dog takes steroids. These suppress the immune system generally and can allow yeast to take control of the skin.

Take your dog to the veterinarian as soon as you notice constant scratching and smelly, greasy skin. Photo: kelseymcdonaldchicago

Symptoms of a Yeast Infection in Dogs

Charles’s signs were those of a well-established infection:

  • Greasy-feeling skin
  • Thickened skin
  • Hyperpigmentation, or darkening of the skin
  • A smell

In the early stages, the dog may just be itchy, which leads to obsessive paw licking. Unfortunately, licking makes the skin damp — which the yeast loves — and the problem gets worse.

As the problem progresses, the dog’s fur may feel greasy or become smelly.

Severe cases that go untreated can end up losing hair and developing rhino hide.


This is down to that most wondrous of instruments: the humble microscope.

Your vet may press a piece of clear adhesive tape to the problem area and then stain the sample. The sticky tape is then stuck to a microscope slide and examined.

Malasezzia has a distinctive appearance that looks just like tiny cottage loaves.

Treating Yeast Infection

To explain this, I’ll give you a scenario where the yeast infection isn’t treated.

Let’s imagine Charles’s caregiver had phoned up and had the usual steroid tablets dispensed.

Steroids are a potent anti-inflammatory that take the itch down, but they also suppress the skin’s immune system — a perfect storm, as far as yeast is concerned. Taken to the extreme, dogs like Charles would soon look like bald, greasy rhinos.

And if Charles’s caregiver thought the allergy was responsible and increased the dose of meds, there’s a risk of inducing even more serious side effects.

Eliminating the yeast is important in reducing the background level of itch, so the dose of anti-itch meds can be kept to a minimum.

Watch this video of a dog recovering from a host of skin ailments, including an itchy yeast infection:

YouTube player


Key to treatment is using an antifungal that’s effective against this unwanted invader.

There are 3 main ways of treating yeast infections in dogs:

  • Shampooing: There is an excellent shampoo called [easyazon_link identifier=”B00061MP5G” locale=”US” tag=”p51capital07-20″]Malaseb[/easyazon_link], which kills malassezia and bring things under control. It must be used every 2–3 days at first.
  • Topical treatments: These include medicated creams supplied by your veterinarian, which are ideal for localized areas such as between the toes. For larger areas of skin, such as the groin or armpits, there are special wet wipes that are infused with an anti-fungal agent. Tip: Tear these in half to make them last a little longer.
  • Oral medication: The severest of cases may need an oral medication, such as ketoconazole (also used to treat ringworm), to make the skin a truly hostile place and have the malasezzia packing their bags.

Treatment isn’t a quick fix and can take several weeks before the problem eases.

Indeed, for some dogs predisposed to yeast infections, it is a case of control rather than cure with regular Malaseb washes to keep the yeast population suppressed.

Yeast may take advantage of skin weakened by deep scratching and proliferate in warmer weather. Photo: doublecompile

Tackling Underlying Issues

These would include treating allergies.

But if your dog has allergies and the treatment isn’t working, do not automatically increase the dog’s meds, such as steroids. Doing so can further weaken the immune system, which may actually encourage yeast infestations.

Instead, it’s better to up the ante and battle the yeast directly with the medications mentioned above.

If you suspect yeast is causing your dog a problem, speak with your veterinarian about how to control it.

In the early stages, your vet can offer a simple shampoo solution.


This pet health content was written by a veterinarian, Dr. Pippa Elliott, BVMS, MRCVS. It was last reviewed Dec. 17, 2018.