PET CORNER
March 20, 2015

Yeast (Malassezia) dermatitis in dogs

Yeasts are the spore-like forms of fungi; Malassezia dermatitis is a fungal infection of the skin.

Yeast infections are itchy, crusty, and smelly. Often a dog starts out with a rash or with simple itching, but the skin thickens to an elephant skin appearance. The itch is extreme and the odour can be especially troublesome.{{more}} Parts of the body or the entire body can be affected. Mostly dogs are affected, but cats can get yeast infections as well.

Where would a dog get a yeast infection?

Yeast happily live on most normal skin and in ears and anal glands. To get a yeast infection, conditions on the skin surface have to change to favour the proliferation of the yeasts. The yeasts in small normal numbers are harmless, but when the yeasts are present in large numbers, disease results.

So, what conditions lead to a yeast proliferation?

An increase in skin oils (which often occurs in an allergic flare up) would be the most common situation. Sometimes there is an immune deficiency that allows the yeast proliferation. Some animals are battling seborrhea (excessive oil production of the skin) and thus are naturally predisposed to the yeast proliferation. Some animals are actually allergic to the yeasts themselves. The most important thing to realize is that while a yeast infection is not contagious, it tends to recur, unless the underlying allergy, seborrhea, or other problem is controlled.

The following breeds are predisposed genetically to yeast infections: the West Highland White Terrier, Basset hound, Cocker spaniel, Silky terrier, Australian terrier, Maltese, Chihuahua, Poodle, Shetland sheepdog, Lhasa apso, and the Dachshund.

How is this confirmed?

There are several testing methods to confirm the overgrowth of yeasts: impression smear (pressing a microscope slide on the skin to collect yeast organisms); Scotch tape sampling (pressing a piece of clear tape to the skin to collect yeast organisms); skin scraping with a blade (scraping the skin with a blade to collect yeast organisms); cotton swab (rubbing a moistened cotton swab on the skin to collect yeast organisms); skin biopsy (removing a small plug of skin with a biopsy punch with a local anesthetic. This is the most invasive choice, but provides substantially more diagnostic information.)

Very few yeasts need to be seen under the microscope to confirm yeast infection.

How do we get rid of it?

Treatment can be topical, oral, or both. Topical treatment is best used for localized spots of infection, while oral medication would be better applied to larger infected areas. If the yeast infection is recurrent or if you wish to supplement oral medication, topical and oral treatment can be combined.

Treatment of the underlying cause

It is important to realize that yeast overgrowth occurs in response to a primary problem, be it allergy, seborrhea or something else. If the underlying problem is not controlled, yeast dermatitis is likely to periodically recur. It is common for allergic dogs to require some kind of periodic, if not on-going, anti-yeast therapy.

For further information, contact: Dr Collin Boyle
Unique Animal Care Co Ltd Tel: 456-4981

Website: www.uniqueanimalcare.com