Arthritis
Atopy (Inhalant Allergy)
Bufo Toad Poisoning
Cat Home Safety Tips
Collar Hazards
Common Things to Watch for
Dental Disease in Pets
Diabetes
Dog Safety Tips
Feline Heartworm Disease
Mallassezia (yeast) Dermatitis
Reasons to Neuter
Noise Phobia in Dogs
Weight Problems in Pets
Otitis (Ear Infections)
Parvo Virus
Pruritis (Itchiness)
Rabies
Seizures and Epilepsy
Senior Pets
Reasons to Spay
Toxoplasmosis, Cats and Women
Malassezia pachydermatis, a yeast that is a normal inhabitant of healthy skin and
ears of dogs and cats. But in animals with allergies (especially atopy) and other
dermatoses such as seborrhea, this normally harmless organism can become
pathogenic.
Although it can occur in any breed of dog, there are certain breeds that are much
more prone to developing Malassezia dermatitis. This includes the small terrier
breeds such as the Silky terrier, Australian terrier, and West Highland white
terrier. Non-terrier breeds at increased risk include the Chihuahua, Poodle,
Dachshund, Cocker Spaniel, Springer Spaniel, Maltese, Newfoundland, and
German Shepherd.
Dogs with Malassezia dermatitis typically have skin lesions on the underside of
the neck, the armpits, and the belly and inguinal areas. Lip folds, the skin
between the footpads and toes and around the anus are also frequently affected.
In affected areas the skin can be greasy and scaly, and it may be hyperpigmented
(darkened) and lichenified (thickened). Affected dogs are also extremely itchy
and have a bad odor that comes back soon after bathing.
Cats with Malassezia dermatitis are also very itchy and may have red, scaly skin,
chin acne, foot infections and ear infections.
How is Malassezia diagnosed? One of the best ways to diagnose Malassezia is
to do a skin scraping of the affected areas and look for the yeast cells under a
microscope. I also use the "scotch-tape" method, where I press a piece of clear
tape onto the skin. I then remove the tape and place it onto a microscope slide
with a drop of staining solution and examine it for yeast cells under a microscope.
How is Malassezia treated? Since Malassezia is not a bacterium, antibiotics are
ineffective against it. Rather, systemic and topical antifungal medications must
be used instead.
Ketoconazole (Nizoral [R]) tablets are frequently used in dogs with Malassezia
dermatitis. Treatment needs to be continued for at least 3 weeks, and it is
highly recommended to monitor liver enzymes while on this medication, as it
may be hepatotoxic (cause liver damage) in some dogs.
I highly recommend using the herb "milk thistle" when giving potentially liver
toxic drugs to dogs. This herb contains "silymarin" a powerful antioxidant that is
believed to have a protective effect against liver toxins. In fact, milk thistle is
commonly used in Europe as an antidote for certain types of poisonings.
Itraconazole (Sporonox [R]) is another antifungal medication that can be used. It
is more expensive than ketoconazole but less likely to be associated with liver
problems. Cats also tolerate this medication better than ketoconazole, which
usually causes them to lose their appetite.
Topical therapy is also very important when treating Malassezia. If the animal is
greasy and scaly an anti-seborrheic shampoo containing sulfur and benzoyl
peroxide like Sulf OxyDex [R] can be used to de-grease the animal. This is
important because the greasy exudate on the skin facilitates the growth of
Malassezia and impedes the action of antifungal agents.
There are a number of other shampoos that are also very effective against this
pathogen including those containing chlorhexidene such as Hexadene [R] and
Chlorhexaderm [R], or miconazole, an antifungal agent, found in Dermazole [R].
Resizole [R], a leave-on lotion containing miconazole can be applied to affected
areas between baths to help speed up healing.
Animals that are extremely pruritic (itchy) may benefit from receiving oral
prednisone tablets or Temaril P [R], a combination antihistamine/prednisone
tablet, for a short time to give them some relief from their constant itching and
scratching. And although antibiotics are not effective against Malassezia they
may be necessary if the animal has a concurrent bacterial skin infection.