Cats can develop food allergies when their immune system overreacts to a food substance it has previously been exposed to. The foods typically associated with food allergies in cats include beef, fish, chicken, and dairy. However, cats can develop an allergy to an ingredient they have consumed for a long time. An animal cannot develop an allergy to a food that it has never been exposed to. Limited research has been performed in this area and there may be other allergens that have not yet been identified.

Symptoms of food allergies in cats include constant itching that does not change seasonally, licking, scratching, overgrooming, and biting. Other symptoms may include vomiting, diarrhea, flatulence, red and inflamed skin, chronic ear problems, and poor growth in young cats. Since chronic itching associated with food allergies can also be caused by other conditions such as external parasites, bacterial infection, yeast infection, or other allergies, additional testing is often recommended to determine the cause(s) of your cats skin condition.

The gold standard for diagnosing a food allergy is to feed the cat a strict hypoallergenic diet for 8 to 12 weeks to evaluate for improvement of symptoms. This means that no additional treats, flavored medications, or even certain formulations of medications can be administered. Some food-allergic cats who fail to respond to one diet may improve on another diet. If your cat has a food allergy and is fed an appropriate hypoallergenic food, symptoms can take up to 10 weeks to resolve. It is important to ensure that there are no other food sources available during this time.

To manage food allergies in cats, it is important to find and avoid the food ingredient responsible for causing the skin and/or gastrointestinal signs. Some cats may react dramatically to even trace levels of an offending allergen, requiring carefully controlled hypoallergenic foods, while other cats may have a higher tolerance and do well on a specific novel protein diet. Some cat foods available in retail stores may tout that they are ‘limited-ingredient’ or do not contain the ingredient(s) that your cat is allergic to, but it is important to note that, unlike veterinary diets, retail pet foods are not manufactured with the extreme health and safety protocols to prevent cross-contamination. Once you have found a diet that works for your cat, you will need to continue that diet long-term, avoiding cat treats.