Do you suspect that your cat has food allergy? Pets, like people, can be allergic to certain types of foods. We commonly diagnose this during annual wellness examinations. Food allergy can be tricky to diagnose. It often requires several months to manage symptoms and get a final diagnosis.

What Are the Signs of Food Allergies in Cats?

Food allergy in cats presents mostly commonly as miliary dermatitis or small crusting scabs on the neck and body. Many cats will also have a history of frequent hairballs.

Common Signs:

Less Common Signs:

What Foods Commonly Cause Allergy in Cats?

Beef and chicken are the most common sources of food allergy in cats. Beef, chicken, beef by-products, and chicken by-products are high-quality sources of protein commonly used in cat foods. By-products may include bone meal and fats from both beef and chickens.

Many commercial pet food companies advertise corn and grains as causes of food allergy. However, research overwhelmingly does not support this claim.

How is Food Allergy Diagnosed?

There is no single test that is specific to diagnose food allergy. A thorough history, including diet and treats, and physical examination are vital to this diagnosis. Often, food allergy is suspected or diagnosed with this alone. Other skin tests such as cytology and culture may be conducted to rule out other causes. Fleas, mange, and bacterial or fungal infections may be present as well. Blood work may be performed to rule out other causes, particularly when symptoms of diarrhea and vomiting are present. However, none of these tests specifically identify food allergy. To definitively diagnose food allergy, we must complete a dietary elimination trial.

How Do We Complete a Dietary Elimination Trial?

Eliminate ALL beef and chicken in the diet.
Choose a new diet that does not contain beef or chicken. This includes treats, table scraps, flavored toys, rawhides, supplements and vitamins. Some heartworm preventative prescription medications are flavored and may need changed as well. We are happy to discuss alternative medication sources and brands for food allergy patients.

Eliminating beef and chicken can be tricky.
This requires close inspection of each food label. Many labels advertise “turkey” or “fish” but still contain beef by-product or chicken meal. Ingredients that do not indicate source, such as “animal fats” or “bone meal” are usually from beef and chicken sources and must be avoided, too.

“Grain free” diets are not recommended – and not necessary.
Since food allergy is most commonly caused by beef and chicken, these are the target proteins eliminate.

Choose a diet that the pet has never had before.
Choose a diet that is affordable and easy to find. This does not necessarily need to be a prescription diet. These ingredient-specific diets are generally more expensive as they guarantee exclusive protein sources such as fish or lamb.

Complete a trial period with the new diet.
Feed the new diet for minimum of 12-16 weeks. During this time, you should note decreased itchiness and improvement in the clinical signs. Note that if your pet is inadvertently fed something with beef or chicken during this trial period, the trial must start over. At the end of the trial period, your pet should be re-evaluated for response to treatment. Occasionally, several food trials are required to identify the allergy culprit and manage the allergy.

How Is Food Allergy Treated?

Most importantly, food allergy is treated by identifying the allergen and eliminating it from the diet. Some pets can suffer relapses of clinical signs when the smallest amount is consumed. This is similar to a person with peanut allergy. Only a small amount is needed to trigger the allergy. Once an appropriate diet has been determined, the patient should remain exclusively on that diet. It is possible the patient may do well on the new diet for several years and later develop an additional allergy. In these cases, we recommend repeating the elimination food trial with a new protein or a prescription hydrolyzed diet.

What if We Can’t Find a Diet That Improves Signs?

Occasionally, pets do not improve, or do not adequately improve, with ingredient-specific diets. These pets may require a prescription diet or additional therapy to control allergy symptoms.

Prescription Hydrolyzed Protein Diets: These diets are relatively new. Hill’s Science Diet Z/D Ultra, Purina HA, and Royal Canin Duck and Pea or Royal Canin HP are all acceptable diets. Your pet may have a preference for palatability. An elimination diet should be repeated with a hydrolyzed protein diet. If the diet helps resolve allergy signs, it should be fed indefinitely.

Investigate Other Allergies: It is very common for pets that suffer from food allergy to also have concurrent seasonal, flea or environmental allergy. In these patients, we recommend additional blood or skin testing. Dust mite and pollen allergies are common. Desensitization therapy is recommended in these patients.

Flea & Tick Treatments: We recommend year-round flea and tick preventative in all of our patients. This is especially important in patients with allergy.

Symptomatic Treatment: Additional therapies are available for treatment of symptoms such as itch that are not completely controlled by diet and desensitization. This includes:
Zyrtec (Cetirizine): This is an over-the-counter allergy medication that is safe for administration to your cat. Do NOT use Zyrtec-D. Please ask about specific dosing for your cat.

Can I Feed My Pet Treats?

As part of the elimination trial, pets cannot be fed treats. Once the trial is over, and an appropriate diet has been determined, the veterinarian may recommend specific foods that comply with the special diet. One food that can be utilized for administering medications is marshmallows.