Food Sensitivity
What is a food sensitivity?
A food allergy is one of the most common allergies or hypersensitivities known to affect dogs and cats. In a pet with an allergy, the immune system overreacts and produces antibodies to substances that it would normally tolerate. In an allergic reaction to a food, antibodies are produced against some part of the food, usually a protein or complex carbohydrate. Since antibody production is required for an allergy to develop, food allergies usually manifest after prolonged exposure to one brand, type, or form of food.
What are the clinical signs of food allergies in dogs?
In the dog, the signs of a food allergy are usually itchy skin, paws, or ears or digestive disturbances such as vomiting or diarrhea. Other more subtle changes can also occur, including hyperactivity, weight loss, lack of energy, and even aggression.
What are the clinical signs of food allergies in cats?
Cats with allergies often present with chronic, year-round itching and skin inflammation. This itching typically affects the face, ears, belly, groin, armpits, and the legs/paws. These cats are so itchy that they often over-groom themselves, causing significant trauma (wounds, abrasions) and hair loss.
Affected cats may also develop recurrent infections of both the skin and ears. In some cats, these infections may be the only clinical sign of food allergies.
In some cases, cats with food allergies develop gastrointestinal signs, such as vomiting or diarrhea, in addition to their skin issues. These cats may develop itching around the rectum, which leads to scooting. Cats with food allergies may also have frequent bowel movements, or strain when they are defecating.
How is a food allergy diagnosed?
The best and most accurate method of diagnosing a food allergy is to feed a hypoallergenic diet for eight to twelve weeks as a food trial called an elimination trial. To be a true elimination trial for your pet, this special diet must not contain any ingredients that it has eaten in the past. It also requires that no other foods, treats, or supplements are fed during the trial period, including flavored vitamins and certain parasite preventives.
If your pet's allergy symptoms resolve while on the food trial, the next step is to perform a food challenge by re-introducing your pet's old food. If your pet's symptoms resolve with the food trial AND return within one week of a food challenge, your pet has been definitively diagnosed with a food allergy.
There are blood tests that may indicate whether the pet is allergic to specific foods. These are called serum IgE tests, and your veterinarian will discuss whether they would be of benefit in diagnosing your pet's condition. There is some evidence suggesting that this blood testing is not as effective as food elimination trials.
