Malassezia Dermatitis in Cats

There are different types of dermatitis which can affect a cat. Malassezia dermatitis is caused by the yeast known as Malassezia pachydermatis. We need to ensure we don't confuse the former (the disease) with the latter (the yeast). This fungus is located in the stratum corneum of the skin on cats. As a common bacteria in the skin of our cats, the presence of this yeast prevents the development of other fungi which might be pathogenic.

Infection may be located on the face, ears, groin, armpits, extremities, interdigital area and ventral part of the neck.

Malassezia pachydermatis causes inflammation due to the release of metabolites of enzymes such as lipases that alter the hydrolipid sheet of the skin. At the same time, it presents surface antigens that generate an immune reaction. It also produces a proenzyme called zymogen that activates complement, which is a component of the immune system. The itch is produced by proteolytic substances released by the body before this process.

The clinical signs of malassezia in cats include:

• Feline acne
• Itchy waxy external otitis
• Exfoliative dermatitis
• Alopecia
• Erythema
• Dry or oily seborrhea
• Self-trauma
• Scabs
• Hyperkeratosis and hyperpigmentation
• Lichenification (thickening of skin)
• Rancid smelling lesions

Since the itchiness can seriously irritate the cat, they will do what they can to relieve it. This means they will often scratch their face, resulting in worsening the sores or creating new wounds (self-trauma).

A differential diagnosis for a cat that exhibits some of these clinical signs indicative of malassezia dermatitis could include the following:

• Adverse reaction to food
• Allergy to a flea bite
• Demodicosis
• Scabies
• Superficial pyoderma
• Atopic dermatitis
• Keratinization defects

Also, it’s important to note that many of these could be the original cause.

Malassezia dermatitis is diagnosed according to the cat's symptomatology and by means of cytology, i.e. looking at a sample under a microscope. Subsequent observation and analysis will reveal the yeast to be elongated and oval ‘shoe-shaped’ with a unipolar orifice. Observation of up to 2 yeasts in the field is considered normal. More than 4 or 5 yeasts per field, for a skin sample, and more than 10 if it is an ear canal sample, constitute a positive test.

Treatment of Malassezia infection is based on the use of antifungals, specifically:

• Ketoconazole (systemic) at a dose of 10 mg/kg, every 24 hours for 3 weeks.
• Itraconazole (oral) for cats at a dose of 5 mg/kg, every 24 hours for 3 weeks.
• Shampoo with ketoconazole or miconazole with 2% chlorhexidine, twice a week.
• Topical creams with some imidazole for mild focal lesions.

In some cases, this alone will be sufficient to stop excess growth and the remission of sores. However, in other cases further action will be necessary to detect and treat the specific underlying causes of the excessive growth, and control the Malassezia through the use of medicated shampoos.

In the case of Malassezia otitis in cats, antifungals such as miconazole, nystatin or clotrimazole should be used in successive combinations with antibiotics and corticosteroids for secondary infections and itching.

Under no circumstances should the cat be self-medicated, since only a professional can diagnose the excessive yeast proliferation and determine the best treatment.

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

If you want to read similar articles to Malassezia Dermatitis in Cats, we recommend you visit our Infectious diseases category.