Food Allergies

Food Allergies

By Kimberly Brito

Food allergies are often a frustrating year-round issue for both itchy pets and their concerned owners.

Thankfully with the advent of specialty diets, relief is a reality for many patients suffering from food allergies. But what exactly is a food allergy and what signs should you look out for? A food allergy is when the body’s immune system overreacts to a harmless food source.  The most common component of a diet that may cause an allergic response is a protein. Examples of common proteins that may elicit a food allergy include: beef, chicken, fish, and possibly any proteins of which pet has been previously exposed. Carbohydrate sources such as wheat and corn may also cause an allergic response, but they are less common.    

The food allergen may affect the gastrointestinal tract, but in dogs and cats the skin is most often affected. In dogs, the most common signs include intense itching, licking, chewing of their paws, flank, groin, neck, and ears. Cats with food allergies may have itchiness and scabbing around their face and neck. Animals with gastrointestinal signs may have vomiting and diarrhea. Recurrent ear infections, especially in canines, may also signal a food allergy.  


Currently, there are no reliable allergy blood tests to determine food allergens. Therefore, food trials are used to rule out a food allergy by placing the pet on a selected prescription diet for at least 3 months. It is essential that no other foods or treats are fed during the trial, as it may interfere with the results. The owner may use the prescription kibble as treats, or even freeze the prescription canned diet. Some medications and preventatives may contain flavoring that will also interfere with the food trial, so it is important to use an alternative product. Sometimes additional therapies such as antibiotics and steroids may be necessary to decrease the itchiness of the pet at the beginning of the food trial or to treat a secondary bacterial infection.

Hypoallergenic diets are unique because they contain a single novel protein or carbohydrate that the dog or cat has not consumed. Examples of prescription food diets include: venison and pea, duck and potato, rabbit and pea, and several other combinations of proteins and carbohydrates. An alternative to a novel protein is a hydrolyzed protein diet, in which the protein is broken down so it remains undetected by the immune system. Chicken and soybeans are often used as the hydrolyzed protein. Historically, novel proteins have been chosen for a food trial, but newer hydrolyzed diets may be beneficial. Your veterinary professional can help you choose which diet(s) are best for your pet. Once the trial is successfully completed, the original over-the-counter diet may be reintroduced to challenge the immune system.

Unfortunately, there is no cure for food allergies, but continued food therapy is a promising treatment. Sometimes the exact protein or carbohydrate is not necessarily identified during a food trial. As long as the animal remains on a strictly hypoallergenic diet, the exact protein does not have to be identified for the food allergy to be well controlled. With compliance from the owner and pet, food allergies are one disease that can have a great turn around for the life of the animal.