Malassezia Dermatitis in Dogs

Many veterinary professionals believe that Malassezia dermatitis is secondary to another condition such as diabetes, Cushing’s syndrome, hyperthyroidism, and allergies. It is more commonly found in dogs that have a weakened immune system from a pre-existing condition or recent illness. There is also evidence of a genetic component in certain breeds.

Malassezia dermatitis is caused by a yeast called Malassezia pachydermatis that is commonly found in the ears and on the skin of dogs. Although it is a normal occurrence, in some cases the yeast grows faster than usual and causes a yeast infection and dermatitis. Most cases of Malassezia dermatitis are due a living environment that is too warm and moist. Also, there are certain breeds that are predisposed to this condition such as Dachshunds, Cocker Spaniels, West Highland White Terriers, Basset Hounds, and Poodles. Because the yeast is commonly found in the ears, this condition can also include ear infections (otitis externa) and deep tissue infection (cellulitis).

The most common signs of Malassezia dermatitis are:

• Affected areas typically appear on the abdomen, underarm, neck, groin, between toes, on lips and ear folds, inside the ear, and in the anal area
• Skin irritation
• Hair loss
• Oily or greasy skin and hair
• Gray or white scales
• Redness and inflammation
• Bad odor
• Abnormally dark areas of skin
• Thickening of the skin
• Ear infection (scratching at the ears, whining, head rubbing, and redness of the ear)

Types

This condition can affect the entire body or just small areas of the skin, but the ears and folds of the skin are the most common areas where this yeast is able to take over. The majority of experts believe that Malassezia dermatitis is a secondary condition in dogs with certain disorders. Some of the most common illnesses include:

• Bacterial (staphylococcal) pyoderma
• Demodicosis
• Diabetes mellitus
• Endocrine disorders
• Food allergy
• Parasitic infestation
• Seborrheic or atopic dermatitis

The cause of Malassezia dermatitis is the Malassezia pachydermatis fungus (yeast). However, veterinary professionals believe that there are many other risk factors that increase the chances of your dog getting this condition. Some of these include:

• High temperatures over 80 degrees Fahrenheit
• Increased humidity
• Weak immune system

Certain breeds such as:

• Basset Hounds
• Chihuahuas
• Cocker Spaniels
• Dachshunds
• German Shepherds
• Golden Retrievers
• Jack Russell Terriers
• Labrador Retrievers
• Lhasa Apsos
• Maltese
• Poodles
• Shetland Sheepdogs
• Shih Tzu
• Springer Spaniels
• West Highland White Terriers

Give your veterinarian all the details about your dog’s medical history and the symptoms you have seen recently. Even though the condition may seem obvious to you just by looking at your dog, the veterinarian will need to rule out other disorders to confirm the diagnosis because there are many other illnesses that can present in the same way. A physical examination will be done including vital signs, behavior, auscultation, palpation, skin scraping, and tissue samples.

These samples will be tested with Methylene Blue or another type of stain to determine the number of yeast cells in the tissue. A normal amount is approximately three to six per high power field (hpf) but if your dog has Malassezia dermatitis, the amount of yeast cells will be much higher. In addition, the veterinarian will run some other laboratory tests such as a urinalysis, complete blood count (CBC), chemistry panel, and blood culture. Immunoglobulin E (IgE) testing is also helpful to determine if there is an allergy involved.

Malassezia dermatitis can be difficult to treat if there is an underlying condition that has not been addressed. Your dog can be treated topically, orally, or both, depending on the severity of the dermatitis and the underlying cause, if there is one.

Topical Treatment

If the condition is localized to small areas, a miconazole cream can be used.

Oral Medication

Some oral drugs that are effective in treating Malassezia dermatitis include fluconazole, posaconazole, ketoconazole, itraconazole, and itraconazole. If your dog has an ear infection, antibiotics and ear drops will be given.

Shampoo

A shampoo that removes lipids from the skin is important in eliminating the infection because Malassezia is attracted to lipid enriched skin. Some shampoos your veterinarian may suggest are those that contain benzoyl peroxide and selenium sulphide. Also, antibacterial shampoo iodine, lime sulfur, and vinegar are sometimes used.

You must be sure to follow your veterinarian’s instructions carefully to clear up the dermatitis. Some of these shampoos and medications can be dangerous if not used properly so call your veterinarian if you have any questions. You will have to continue to visit the veterinarian regularly to evaluate the progress of the treatment.