Fungal Infection of the Skin (Malassezia dermatitis) in Dogs

Malassezia dermatitis is an itchy, uncomfortable condition in dogs. Dogs with patches of scaly, dry, or crusty skin that are causing itchiness require prompt veterinary attention.

The severity of Malassezia dermatitis depends on how much of the skin is infected, and how long the disease is present before treatment begins.

Some dogs only have a few small localized patches of dermatitis on certain parts of their body, while others develop skin changes all over their bodies. Many dogs develop waxy, black discharge from the ears.

Dogs with skin folds where heat and moisture get trapped against the skin are at greater risk of Malassezia dermatitis. Dogs living in warm, humid climates are also more susceptible. Some dogs in temperate climates are more affected during the summer months.

Dogs that are hypersensitive to allergens including food, flea bites, and the fungus itself are at greater risk.

Dogs with underlying health issues including endocrine diseases, such as hypothyroidism, or other skin conditions are also at greater risk.

Dogs who have had this condition for a long time develop thickened patches of darkened skin along with the itchy lesions.

This condition is not typically contagious, therefore other animals in the home are not at risk.

In some cases, dogs become so itchy that they become frenzied, desperately trying to scratch their face to relieve the irritation. This can lead to self-mutilation which can then develop into secondary bacterial infections.

Malassezia dermatitis is skin inflammation caused by the fungus Malassezia pachydermatis. This fungus is commonly found on the skin, in the ear canals, and around the anus of healthy dogs, and usually does not cause any symptoms. Only in certain circumstances does the fungus reproduce quickly enough to become symptomatic.

Circumstances in which Malassezia pachydermatis proliferates include:

• When there is an underlying skin condition that increases the amount of oil on the skin
• When the climate is warm and wet
• Areas where the body retains moisture, such as between the toes and in skin folds
• When there is damage to the skin that allows the fungus to access the lower layers of the skin
• When the body is not able to effectively fight off infection due to immune dysfunction or immunosuppression
• When the dog is hypersensitive to allergens or flea bites
• When there are other underlying issues such as hypothyroidism or other skin infections

Lesions are typically found around the lips, ears, feet, armpits, and neck.

Diagnosis of Malassezia dermatitis aims to identify the fungus and rule out other possible causes of skin irritation.

Diagnostic tools include:

• Physical examination
• Fungal culture
• Skin cytology

Treatments include antifungals, either in the form of creams and shampoos to be applied topically, or pills to be taken orally. In some cases, both oral and topical treatment are required.

In cases where underlying conditions cause this condition, treating these underlying conditions is required for recovery.

In cases where other opportunistic infections happen at the same time, treatment for them is also required.

The prognosis for Malassezia dermatitis is good with treatment. Usually, symptoms improve within a week of treatment. Underlying conditions and associated infections must be managed to avoid recurrence.

Malassezia dermatitis is not typically infectious. Preventive measures include keeping skin dry and cool, treating possible underlying conditions early, and avoiding overuse of steroids to prevent immunosuppression.

Malassezia dermatitis is common in dogs.

Antifungals