Food allergy in pets

Pets can react negatively to foods in different ways, most commonly known as food allergy or food intolerance. Food allergies can be hard to distinguish from food sensitivity and in practice, these two distinct reactions are usually lumped together. Food allergies (example wheat allergy) have an immunological basis, whereas food intolerance (example certain toxins) can develop without involvement of the immune system.

Food allergies correlate to about 10-20% of the skin allergies in pets, which is third most common behind flea allergies and environmental (or airborne) allergies. The most common causes of dietary sensitivity in dogs and cats include beef and dairy products, other meat proteins such as chicken and eggs, lactose and gluten though all dietary protein can potentially be allergenic to pets. A review from 1998 of 8 different studies indicates that beef, dairy, and wheat accounted for 66% of the food allergies in dogs while chicken, lamb, eggs, and soy account for 25%.

The mode of action for food allergies occurs at the brush border (inner lining) of the intestine. Most protein is broken down to amino acids, which the animal can absorb. However, a small amount of intact protein can be absorbed and over time this can be enough to elicit an allergic response. Antigens are released based on this allergic response and some of these antigens are able to bypass the protection provided by the immune system. When this occurs, the animal will present clinical signs of allergies such as pruritus (common skin problem often noticed by itching) and possibly gastrointestinal disorders.

To determine a true food allergy, the pet must be removed from the offending diet and fed a hypoallergenic diet. Once allergic symptoms clear up, the offending diet should be fed again to see if clinical signs reappear. Clinical signs most commonly include pruritus and gastrointestinal issues. In reality these types of tests are hard to complete because it takes a long time (can last up to 12 weeks) and owners typically are unwilling to re-introduce the possible offending diet back to their pets. There are intradermal tests and blood tests that can be done but these may not be as reliable.

Treatment of true food allergies requires the pet to be fed a diet that does not have the allergen. If the pet is allergic to wheat then wheat should not be in the diet. There is no universal hypoallergenic diet but several types have been successful. They are successful because they have not been traditionally fed in commercial pet diets. The most common are rabbit, lamb, venison, or various fish species and are normally fed with rice or potatoes as a source of carbohydrates. However, an allergy could develop with these ingredients also. More recently a new option has become available with feeding proteins that have been enzymatically digested so the protein is not large enough (lower than 10,000 Da) to elicit a response.

Research has not shown a sex differentiation for food allergy in dogs or cats. Research on breed effects have not always agreed but here are some breeds that may be more susceptible to food allergies. These breeds include Soft-Coated Wheaten Terrier, Dalmation, West-Highland White Terrier, Collie, Chinese Shar Pei, Llasa Apsa, Cocker Spaniel, Springer Spaniel, Miniature Schnauzer, German Shepherd, Labrador Retriever, Dachshund and the Boxer. Food allergies can occur at any age but up to 33% are seen in dogs less that 1-year of age.

In summary, food allergies are the third most common allergy found in pets and can lead to skin and gastrointestinal disorders. It is imperative for the owner to conduct
the proper testing to determine if a true food allergy exists and then remove the offending ingredient from your pets diet. Loyall Pet Food has a product to meet the need of pets with different food issues. Loyall Lamb Meal and Rice is a great product to improve the health of pets with skin problems.

Reference:
Carlotti, D.N., I. Remy, and C. Prost. 1990. Food allergy in dogs and cats: A review and
report of 43 cases. Vet. Derm. 1:55-62.

Hall, E. J. 1994. Gastrointestinal aspects of food allergy: a review. J. Sm. Anim. Pract. 34:175-179.

Jeffers, J. G., E. K. Meyer, and E. J. Sosis. 1996. Responses of dogs with food allergies to single-ingredient dietary provocation. J. Amer. Vet. Med. Assoc. 209:608-611.

Paterson, S. 1995. Food hypersensitivity in 20 dogs with skin and gastrointestinal signs. J. Sm. Anim. Pract. 36:529-534.

Rosser, E. J. 1993. Diadnosis of food allergy in dogs. J. Amer. Vet. Med. Assoc. 203:259-262.

Vester, B. M. and G. C. Fahey, Jr. 2007. The importance of nutrition in coat quality and skin health of dogs and cats.

Watson, T.D.G. 1998. Diet and skin disease in dogs and cats. J. Nutr. 128:2783S-2789S.

White, S. 2001. Update on food allergy in the dog and cat. World Small Animal Veterinary Association World Congress.