Food Allergies in Dogs and Cats

September 6, 2022

Dogs and cats can experience allergies to a variety of things including fleas and environmental contaminants such as mold and pollen. A rarer form of allergies in dogs and cats, though equally problematic, are food allergies. Food allergies are statistically rare – only 0.2% of dogs and 0.1% of cats experience true food allergies. Despite this condition being very rare, any pet suffering from chronic skin conditions or GI upset should be evaluated for dietary allergies.

Upon the mention of allergies to food, most people assume that their pet is allergic to grain which is something being diagnosed more and more in people however, grain allergies are extremely rare in pets. In fact, a diet completely devoid of grain can actually cause devastating consequences to dogs in the form of heart disease. When pets experience a true food allergy, the most common offender is actually protein. Proteins are found in abundance in meat, eggs, nuts and legumes and of these, the biggest culprits that trigger allergic reactions are beef and poultry.

Dietary allergies in pets can have a range of symptoms from GI upset to itchy skin and skin infections. Pets with recurrent bouts of diarrhea or intermittent vomiting without any other known cause may be suffering from a food allergy. In some cases, pets with food allergies may display severely itchy skin on the paws and face and can have recurrent ear infections. Any pet battling with recurrent itching and skin infections or GI upset will likely need a variety of testing to screen for the underlying cause including looking for food allergies.

If we suspect that a pet has a food allergy, the way to diagnose this is to put the pet on a diet trial using a prescription hydrolyzed diet. This is a type of food that still contains protein needed for nourishment of the pet but they have been broken down to such a small molecular level that the body can not recognize it as an allergen. A diet trial is a diagnostic tool that lasts for 4-8 weeks and takes a serious level of commitment from the pet’s owners. During this trial, the pet must be on only the prescription diet with no other sources of food, treats or table scraps. The purpose of this test is to rule out any and all other food sources that could trigger an allergy so if the pet has received a treat that was not part of this diet, we could not accurately say that the pet does not have a food allergy if they are not improving.

At the end of the 4-8 week period, if the pet is still suffering from the allergy, we can definitively say they do not have a food allergy and move on to the next possible cause. If however, the pet’s condition improves then we would be more inclined to think the pet has an allergy to something that was in their previous diet and this can be a very simple thing to manage if we are careful about avoiding the allergen. In some cases, the pet owner may want to push forward to identify the exact protein source that triggered the allergy in the pet such as giving a treat flavored with beef to see if they have a reaction. This can help the pet parent be careful to avoid any foods with beef, beef byproduct or flavoring in the future. In other cases, the owner may choose to just stick to the prescription hydrolyzed diet as it is safe to feed pets long term and will not trigger another reaction by challenging them with diet changes again. Owners that are able to identify the exact underlying allergen and wish to switch to an over the counter limited ingredient diet should still consult with their vet before doing so. A lot of the proteins are very similar in make-up and can still trigger a reaction even if you avoid the diagnosed allergen. For example, pets with beef allergies can sometimes still react to venison or lamb and pets with chicken allergies can still react to any type of poultry as well as eggs. It is very important to read the entire food ingredient label and consult with the vet to see if a particular diet you want to try for your food allergic dog is safe for them.