Yeast infections in pets are itchy, crusty, smelly, and simply unpleasant for both you and your four-legged friend. Just like there are good bacteria that promote health and bad bacteria that can cause illness, there are also good and bad yeasts. Yeasts are naturally present on skin and usually do not cause any problems. Small amounts of them are harmless, but overgrowth can lead to serious issues.
For a yeast infection to occur, a change in the skin surface that supports growth must occur. Infection often starts with a rash or excessive itching, and can develop into extremely irritated and thickened elephant-type skin. Yeast infections will tend to recur if the underlying cause is not identified and corrected. Adverse food reactions, hormonal disturbances, bacterial infections, pre-existing skin conditions, and the long-term use of some types of medications can create favourable conditions in the skin for yeast to thrive. (1,2)
If your pet has recurring yeast infections, determining if he is experiencing an adverse food reaction may help to improve the situation. Food reactions in pets often mimic other conditions, such as environmental allergies, so diagnosis can be challenging. Limited ingredient diets containing novel protein sources, hydrolyzed protein diets, and home-cooked elimination diets are some of the options to consider if you suspect your pet is having an adverse food reaction.
Limited ingredient diets (L.I.D.) offer a single source of meat protein with as few additional ingredients as possible to meet nutritional requirements. Novel ingredients that are not commonly used in pet foods, or not commonly associated with adverse food reactions, are typically used in L.I.D. recipes to increase the chances of success. Hydrolyzed protein diets contain protein that has undergone a special process to break down the protein into smaller fragments, so they are less likely to cause a reaction. Home-cooked diets may be used in elimination-challenge trials to help pinpoint the offending ingredients. These trials should be performed under the supervision of a veterinarian. If a home-cooked diet needs to be followed long-term, it is important to follow a diet that has been formulated by a nutrition professional to ensure that the diet contains all of the nutrients your pet needs.
It has been suggested that eating foods that contain carbohydrates increases the risk of a dog or cat getting yeast infections. Yeast needs carbohydrates for growth, but does eating a diet that contains carbohydrate increase the risk of yeast infections? The short answer – not likely. When carbohydrates are consumed, they are broken down into glucose to provide a key source of energy. The amount of glucose in the blood is tightly controlled. If dietary carbohydrate is not available to maintain blood glucose levels, amino acids from protein can be converted to glucose to keep levels in the ideal range.
The confusion about carbohydrates causing yeast infections may have arisen due to the increased prevalence of bacterial and yeast infections in pets and humans with diabetes. The high blood sugar present in uncontrolled diabetes creates an environment in which bacteria and yeast can flourish, thereby increasing the risk of infection. However, in healthy, non-diabetic pets, blood glucose levels are maintained at levels that do not promote infection. It is not until the body is thrown off balance due to another illness or allergy that yeast infections are more likely to develop.
Can yeast in pet foods contribute to yeast infections? Again, it is important to remember that there are good yeasts and bad yeasts. Brewer’s yeast, selenium yeast and yeast extract are ingredients made from good yeast that have little chance of causing a yeast infection. However, if you have identified that your pet has an adverse reaction to yeasts through food elimination-challenge trials, you will want to select foods without yeast ingredients.
1. Charach M. Malassezia dermatitis. Can. Vet. J. 1997;38(5):311-314.
2. Faergemann J. Atopic Dermatitis and Fungi. Clin. Microbiol. Rev. 2002;15(4):545-563.
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