Malassezia Dermatitis in Dogs

The fungus known as Malassezia in dogs, despite living normally on the skin, can cause various ailments.

The disease we are talking about today is very particular, as it is caused by a microorganism that normally lives on the skin. When certain changes occur, Malassezia in dogs turns into a pathogenic fungus, causing Malassezia dermatitis and other ailments . Read on!

Malassezia dermatitis in dogs

First of all, it is good to know this microorganism a little more thoroughly. The genus of Malassezia mushrooms was described for the first time around 1874 as a somewhat peculiar mushroom, both in morphology and in lifestyle. Up to 11 different species are currently known, of which the one responsible for the so-called dermatitis in dogs or Malassezia pachydermatis.

Under normal conditions, this fungus lives on the skin of dogs , particularly in the ears, mouth or genital area. Various factors such as regenerating skin keep Malassezia growth in balance .

When the colonies of this fungus are within the limits, its presence is even beneficial, as it prevents other harmful fungal species from starting to proliferate in the skin tissues . However, the genus Malassezia can start growing out of control in certain situations, such as in the presence of:

  • A significant increase in humidity or heat.
  • An increased amount of lipids , i.e. an alteration in the production of the dog’s sebaceous glands.
  • A depressed immune system, the existence of skin allergies or even an excess of skin folds.


As you can see, this fungus is opportunistic, which means that it takes advantage of it to proliferate when other more important diseases occur. One of the main symptoms, and perhaps the most obvious, is the unpleasant rancid smell that begins to give off the dog’s coat . This is due to the scabs, which are often accompanied by itching.

Other characteristic symptoms of Malassezia dermatitis are:

  • Hair loss in the affected area.
  • Red and inflamed skin, a phenomenon commonly known as erythema .
  • Scales and intense itching.

Normally, the area most affected by the infection is the abdomen. Later the dermatitis could develop into pododermatitis, which manifests itself with the hair turning brown between the toes of the paws.

There are some breeds with more predisposition to suffer from Malassezia dermatitis , such as the basset hound , poodle, labrador or shar pei, among others.

Is there a treatment for this dermatitis?

If your dog is showing the symptoms we have mentioned, you should take him to the vet asap. Once there, the doctor will perform a series of diagnostic tests – usually a culture and cell count. If Malassezia infection is confirmed, the first thing to do will be to apply imidazole antifungal drugs .

Depending on the extent of the affected area, the treatment can be carried out in different ways. If the lesion is very localized, topical application of antifungal ointments is usually sufficient . In severe cases, it is necessary to follow a daily treatment with shampoos specially indicated for this type of infection.

After a few weeks, the number of Malassezia colonies will be counted . If it is within the usual limits, it means that the treatment has taken effect. In any case, the vet may choose to prescribe a shampoo anyway, to be used during the following weeks.

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