Skin yeast infections are common in companion dogs. The most frequent culprit is a species of fungal yeast organisms called Malassezia pachydermatis. Because these yeast are part of the normal flora of a dog’s skin, an infection only occurs when they reproduce and colonize without any of the normal controls and inhibitions imposed by a healthy immune system. Fortunately, yeast infections in dogs usually are not hard to treat. The goals of treating a canine yeast infection are to eliminate yeast overgrowth, relieve the dog’s itchiness and other symptoms of discomfort, identify and treat any predisposing conditions, resolve the accompanying skin scaling, greasiness and foul odor, eliminate or at least manage secondary bacterial, viral or fungal infections, and reduce the risk of recurrence.
A number of different protocols are available to treat yeast infections in dogs. In most cases, the attending veterinarian first recommends application of topical anti-seborrheic, antibiotic, anti-fungal and/or anti-yeast medications. These come in a variety of formulations, including medicated shampoos, solutions, dips, lotions, creams, rinses, sprays, wipes and even powders. Some of these topical treatments are benzoyl peroxide, boric/acetic acid, clotrimazole, miconazole, ketoconazole, sulfur/salicylic acid, phytosphingosine, selenium sulfide, terbinafine, lime sulfur, enilconazole and chlorhexidine. There are others. Most topical medications are applied several times a week. Some are supposed to be applied to the dog’s skin and coat daily for a certain period of time.
Prescription oral anti-fungal drugs may be warranted in cases of severe yeast infection, or for those dogs that do not respond sufficiently to topical therapies. Currently, ketoconazole, itraconazole, fluconazole and terbinafine have been used with some success as multi-week, long-term oral anti-yeast treatments for skin infections in dogs. Oral anti-yeast medications typically are given for at least 1 to 2 weeks after all signs of infection have gone away. Usually, the initial course of treatment lasts for a minimum of 3 to 4 weeks, and sometimes longer. Dogs that develop secondary Staphylococcal or other bacterial infections should be treated with oral antibiotics, at an appropriate dose and for an appropriate duration. Dogs with recurrent yeast infections may benefit from something called “pulse therapy.” This involves administering an oral azole anti-yeast/anti-fungal drug either for 2 consecutive days each week, or daily for one week, then taking 1 to 4 weeks off, and repeating the cycle. Azoles tend to concentrate in the skin. Of course, addressing and resolving the underlying cause of any infection is the best way to manage its course. Owners of dogs with skin yeast infections should consult closely with their veterinarian about the potential side effects of any drug therapy, especially if the dog may be used as part of a breeding program down the road.
The prognosis for dogs with yeast infections is generally quite good. Some dogs will require periodic lifelong treatments to manage outbreaks. A veterinarian is the best person to provide advice as to the appropriate treatment options for any particular dog.