Fungal Dermatitis in Dogs

Fungal dermatitis in dogs occurs due to a yeast infection of the skin. The yeast that cause the infection already live on your dog, but usually their numbers aren't large enough to cause infection. If your dog's skin provides an ideal environment, however, these natural flora can grow out of control, causing extreme itching, thickening of skin and a strong, unpleasant odor. Read on to learn more about diagnosing and treating fungal dermatitis in dogs.

Causes and Risk Factors for Canine Skin Yeast Infections

The yeast that cause fungal dermatitis already live on your dog's body. A normal population of yeast on your dog's skin doesn't cause infection, but helps maintain the health of his skin. Certain conditions, however, can lead to overgrowth of your dog's normal yeast. This overgrowth usually causes what's known as a yeast infection of the skin, or fungal dermatitis.

Excessive skin oil production, or a sudden increase in the amount of skin oils your dog produces, is one of the most common causes of canine fungal dermatitis. Seborrhea, a condition which causes the skin to produce too much oil, increases your dog's risk of fungal dermatitis. Immune deficiencies, allergies and poor hygiene can also cause fungal dermatitis.

Some breeds are more vulnerable than others to yeast infections of the skin. These breeds include:

  • Maltese
  • Chihuahua
  • Poodle
  • Australian Terrier
  • Silky Terrier
  • Cocker Spaniel
  • West Highland White Terrier
  • Basset Hound
  • Shetland Sheepdog
  • Lhasa Apso
  • Dachshund

Symptoms of Skin Yeast Infections in Dogs

Fungal dermatitis in dogs is usually caused by a yeast known as Malassezia pachydermatis. As its name suggests, this type of yeast can cause your dog's skin to thicken and become elephantine in appearance. Your dog will develop a rash that is incredibly itchy, crusty and foul-smelling. The rash can cover some or all of your dog's body.

Diagnosing and Treating Fungal Dermatitis in Dogs

Your vet can diagnose fungal dermatitis by swabbing your dog's skin to look for yeast organisms under a microscope. Skin scrapings or skin biopsies might be necessary to make a diagnosis. 

Topical and oral medication can be prescribed to treat your dog's fungal dermatitis. If your dog's infection is widespread and severe, a combination of both topical and oral drugs might be prescribed to clear it up. If your dog has only minor skin lesions, your vet might feel that topical medication is adequate to treating the dermatitis. 

Oral drugs used to treat fungal dermatitis include ketoconazole and itraconazole, which may need to be administered for several weeks. Your vet will adjust the dosage depending on the severity of your dog's infection. Your dog should begin to experience relief from his symptoms in about a week.

Anti-fungal shampoos are often prescribed to treat widespread infections. Smaller lesions can usually be treated with a spot-on treatment. 

If your dog's fungal dermatitis is the result of an underlying condition, such as seborrhea or allergies, then it will keep coming back until you have successfully treated its underlying cause. Dogs with allergies or seborrhea often require ongoing treatment for recurrent fungal dermatitis.