If your cat has a greasy hair coat or recurrent ear problems they may be suffering from Malassezia. This fungal/yeast infection of the skin can be mild or extensive and may indicate that there is an underlying health problem. If your cat has any skin lesions you should make an appointment to see your vet - it may be that the skin disease is an indication that something more serious going on.
What is Malassezia?
Malassezia is often found on the skin of normal animals where it causes no problems. Skin disease develops in animals that have a reduced immune response or damaged skin. Once the skin resistance is reduced the fungus can multiply and spread.
How did my cat catch Malassezia?
There are some underlying conditions that can weaken your cats immune system and make them more likely to get Malassezia infections. These include severe illnesses like diabetes; cancer and feline immunosuppressive virus infection (FIV) and long-term problems like allergies. However, simple changes to the skin (such as constant wetting due to excessive drooling), can result in local infections.
How will I know if my cat has Malassezia?
Cats with Malassezia ear infections will constantly shake their head and scratch at their ears. A thick black waxy material may be seen crusting around the ears and the opening of the ear canal. Acne and chin swelling may be noticed but skin changes can occur at any site. Wherever disease is present the affected area will be itchy so that the cat will want to lick or scratch at the site. Some cats develop disease on their feet and repeatedly shake their feet as if their paws were wet.
What tests will my vet need to do?
Your vet may suspect that your cat has a Malassezia infection just by looking at the skin. A sample of the skin surface can be simply collected using a piece of selotape stuck to the skin and pulled off. This can be looked at under a microscope to identify the yeast. Sometimes Malassezia can be more difficult to find and a culture or skin biopsy may be advised. Culture is performed by rubbing a swab over the affected skin and sending it to a specialist laboratory. The results can take a week or so. Skin biopsy is a minor surgical procedure and requires a full general anaesthetic in cats, removing a full-thickness piece of skin (or several pieces) and submission to a specialist laboratory. Results will take several days. However, even once a diagnosis of Malassezia has been confirmed your vet may want to do some additional tests to see if they can find an underlying cause. These will include blood tests and urine samples for laboratory analysis.
What else could cause these signs?
Your vet will want to rule out parasitic conditions such as Demodex (mange mites) and flea infections; ringworm (a fungal infection) or acne as these can appear similar to, or occur at the same time as, Malassezia. Persian cats can get a particular severe form of acne known as idiopathic facial dermatitis. The commonest cause of ear problems, as described above, is ear mites (Otodectes). These are usually easily diagnosed by your vet examining ear wax material under the microscope.
What is the treatment for Malassezia skin disease?
In mild cases no treatment may be needed although your vet may give you a wash to occasionally clean the skin surface in affected areas. Ear drops can be used to control infection in the ears. For more severe skin lesions special shampoos or skin creams can be prescribed. Treatment with tablets is only used in severe cases. In some cases the infection may completely resolve although in other cats, especially if there is an underlying cause, long-term treatment may be needed.