Annabessacook Veterinary Clinic
417 Route 135
Monmouth, Maine 04259

Food Allergies

Food allergies are seen regularly in dogs and cats and represent 10-20% of all allergic patients. The reason that we pursue the diagnosis of food allergy so strongly is because these patients can basically be “cured” without the use of any drugs by avoiding the ingredients to which the pet is allergic. Most other types of allergies require some form of long-term treatment to “control” the allergy.

The clinical signs (symptoms) of a food allergy may be related to the skin, digestive tract and/or the respiratory system. The most common skin problem is itchiness, which will be shown by scratching, rubbing or licking of the body. Occasionally animals develop rashes, dry or oily skin with scale and flakes (dandruff), or have chronic or recurring ear infections. When the digestive tract is affected, animals may have vomiting, diarrhea, flatulence (windiness), or frequent bowel movements. Keep in mind that animals with food allergies don't necessarily have ALL these signs at the same time. Symptoms may develop at any age and any time of the year. Many animals have been eating the same food for several months or even years before they develop the allergy; therefore, a recent change of diet or food is neither necessary nor expected.

The most common causes of food allergies are beef, pork, chicken, milk, whey, eggs, fish, corn, soy, barley, wheat, and even rice. Since at least some of these ingredients are present in most commercial pet foods, merely changing from one brand of food to another is not helpful in determining if an animal has a food allergy.

The ONLY way to diagnose a food allergy is through the use of a low-molecular-weight hydrolyzed diet, or a hypoallergenic diet utilizing protein and carbohydrate sources to which your pet has never been exposed. Hydrolyzed diets are composed of proteins that have been broken down into pieces too small to induce allergic reactions. For the most part, these diets are palatable and well received by pets. The most commonly used brands are Hills z/d, Purina's H/A, and DVM's EXclude. All can be ordered through veterinarians.

Hypoallergenic diets can also be made at home. In the past, popular diets have included lamb and rice. However, both lamb and rice are now found in many commercial diets and therefore do not represent “novel” food sources. Unique or “different” proteins may include lamb (if it has not previously been fed), rabbit, beans (pinto, Northern, or garbanzo), or wild meats such as elk or venison. Suitable carbohydrates include potato, if rice has been part of the previous diet. After the meat and carbohydrate have been cooked, they may be mixed together at a ratio of one part meat and two-to-three parts carbohydrate. If beans and potatoes are to be used then you should mix them in equal amounts. These home-cooked diets will have fewer calories than “typical” food so your pet will need at least the same volume of food as before, and possibly more. Also be aware that these home-cooked diets are NOT BALANCED and, under no circumstances, can be fed for longer than 8 weeks.

A hypoallergenic food trial must be fed for a minimum of eight weeks to be diagnostic. The intention is NOT to keep your pet on this diet forever, but only to determine if any part of the problem is indeed related to the diet. It is very important that your pet not receive ANY other food or treats during this test. Therefore, treats, chew toys, chew bones, Milkbones, flavored medications, and most vitamin supplements should not be given during this time. It is also important to make sure your pet doesn't raid the food bowls of other pets, nor consume their feces.