Many different microorganisms can be involved in a skin infection, but one of the most common is a type of yeast or fungus called Malassezia pachydermatitis. Malassezia are normally found in small numbers on the skin and in the ears of dogs and cats, but if the skin's normal protective barriers are weakened, the yeast can take advantage of the situation and reproduce rapidly, leading to infection. Allergies are a common underlying problem associated with Malassezia infections.
Pets with Malassezia skin infections are usually extremely itchy. They may lose hair, have areas of red and/or greasy skin, and often have a musty odor. A veterinarian can differentiate a Malassezia infection from other types of skin disorders that cause similar symptoms (e.g., bacterial infections or parasite infestations) by looking at a sample of cells removed from the surface of the skin under the microscope.
Several different types of antiseptics and antifungal medications are available that will kill Malassezia organisms. Topical treatment (e.g., medicated baths, cleansers, and ointments) is usually sufficient in mild cases, but oral anti-fungal medications may be necessary if the infection is more severe. These oral drugs can produce potentially serious side effects, so blood work is often monitored before and during therapy. If a pet is extremely uncomfortable, the veterinarian may also prescribe drugs that decrease itching and inflammation. Any underlying issues such as allergies must be addressed or the infection is likely to return once treatment stops.
Written by: Jennifer Coates, DVM
Last reviewed: October 2, 2008