Yeast Infection and Thrush in Dogs

Yeast infection and thrush both refer to an overabundance of yeast in a dog's body, whether in the digestive system, in the mucous membranes, or on the skin. They're typically caused by one of two yeast organisms – Candida or Malassezia – and often appear quite similar to other conditions, such as skin infections or allergies. A yeast infection is not fatal in itself but may lead to complications if left untreated.

The symptoms of a yeast infection vary depending on where the infection is located though typically a dog may show signs similar to those of an allergic reaction. These clinical signs include:

• Itching or scratching
• Rash
• Foot chewing
• Ear discharge
• Drooling
• Odd odor

Your dog may also show nonspecific symptoms, such as lethargy, loss of appetite, or diarrhea.

Types

Yeast can normally be found in a dog's digestive tract and on the skin. Candida occurs in the mucous membranes, such as inside the mouth or the digestive system, while Malassezia congregates on the skin. These organisms are not harmful if kept in balance by the body's supportive systems, but given the opportunity, they can grow rapidly, which leads to infection and disease.

Most yeast infections in dogs are caused by Candida, which is a type of yeast that thrives on sugar. Candida is normally present in a dog's digestive system, but an imbalance in the dog's body may prompt it to spread. Malassezia is likewise an opportunistic yeast and will grow rapidly given the right conditions, such as when the immune system is failing, showing signs of failure, or when it is weak, or when skin is already irritated.

If your dog is scratching persistently or is showing other clinical signs, bring him into the veterinarian. The veterinarian will conduct a standard, yet increasingly important, physical examination in order to rule out other possible causes, such as allergies or another type of infection. Provide the veterinarian with a complete history, as well as the progression of symptoms you've observed.

A yeast infection can often be diagnosed by identifying the organism under a microscope. This is typically done by examining your dog's skin, stool, or a urine sample, where the yeast can be observed if it is present. A biopsy of any existing lesions may reveal yeast organisms that have infected the area.

Treatment for a yeast infection varies according to the source and extent of the infection. The veterinarian may prescribe a multitude of medication, including a combination of antibiotics and antifungal medication, either as a topical or oral treatment. Topical treatment includes anti-yeast shampoo, medicated wipes, and medicated creams, which may be prescribed to address infections of the skin or around the ears. Oral medications, such as fluconazole or ketoconazole, are used to fight infection in the digestive tract. They are also often administered in cases where topical treatments are not sufficient by themselves.

In order to prevent the yeast infection from recurring, any underlying conditions must also be treated either before or during the infection itself is addressed. Since the presence of yeast in a dog is normal, an infection typically occurs when some other part of the body is weakened – for example if the population of "friendly" bacteria in your dog's digestive tract is low. Depending on the condition, treatment will vary.

A yeast infection can be managed or prevented by providing balanced, nutritional food and by drying your dog well after he gets wet. Because yeast thrives on sugar, cutting sugar and carbohydrates out of your dog's diet may help control the yeast's growth. Talk to the veterinarian about dietary changes that may help speed your dog's recovery, and eliminate treats with any form of sugar, including honey and high fructose corn syrup.

Administer all medication according to instructions, and prevent your dog from biting or scratching, since a yeast infection can spread into cuts or scratches. Prognosis varies depending on the underlying condition for the yeast infection, but most dogs recover fully from the infection following treatment.