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
The cause of Charles’s infection was a yeast, malassezia, which is an inhabitant of canine skin that normally coexists happily 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.
Charles’s signs were those of a well-established infection:
- Thickened skin
- Dark pigment
- 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.
Why Treatment Matters
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 (remember how irritating athlete’s foot can be?), 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:
There are 3 main ways of treating yeast infections in dogs:
- Shampooing: There is an excellent shampoo called Malaseb (affiliate link), which kills malassezia and bring things under control. It must be used every 2 or 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 which are infused with an anti-fungal agent.
- Oral medication: For the worst cases, an oral medication can make the skin a less hospitable place from the inside out.
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.
Why the Warning?
If your dog has allergies but the treatment isn’t working, don’t automatically increase the dog’s meds. Often this does more harm than good because it encourages itchy yeast infestations.
Instead, check in with your veterinarian. In the early stages, your vet can offer a simple shampoo solution. So if your dog itches, think allergies, parasites — and yeast.
This pet health content was written by a veterinarian, Dr. Pippa Elliott, BVMS, MRCVS. It was last reviewed Dec. 17, 2018.