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Is your cat struggling with itchy skin, recurring ear infections, sores, or an upset stomach? These mysterious symptoms can be frustrating to manage—but one possible cause could be a food allergy. While flea allergies and environmental allergens (like pollen or dust) are the most common culprits, food allergies are the third most common type of allergy in cats. Identifying and managing these allergies is key to relieving your cat’s discomfort and improving her overall health.

What are Food Allergies in Cats?

A cat can develop a food allergy when their immune system overreacts to a food substance they have eaten in the past. Over time, their immune system produces antibodies to a protein or complex carbohydrate in her food. As a result, these antibodies cause a food allergy to “suddenly” manifest and afflict your cat.

It’s relatively rare for cats to have food allergies. Only 1% of call cats have them. Of the 1%,  15% of itchy cats have food allergies. Even more, 42% of cats who have both itching and gastrointestinal problems are reacting to food. This can be a food allergy or a food intolerance.

Food allergies can develop at any age, but usually start when a cat is older than four years old.

What Causes Food Allergies in Cats?

As with many mysteries revolving around cats, the exact cause of cat food allergies is still unknown. More research is needed to find out why they occur. However, most believe it to be caused by a genetic predisposition to developing food intolerance or hypersensitivity to allergens in their food.

Although cats can develop allergies to any protein or carbohydrate they have been exposed to, the most common food allergies are:

• Beef
• Fish
• Chicken

In addition, cats can also have allergic reactions to the following foods, though they happen less commonly:

• Wheat
• Corn
• Dairy
• Lamb
• Egg
• Barley
• Rabbit

Symptoms of Feline Food Allergies

The most common symptom with food allergies in cats is constant scratching, especially around the head and neck. This results in licking, scratching, overgrooming, and biting.

Symptoms may also include:

• Recurrent skin lesions, scabs and plaques caused by the scratching, biting and licking.
• Self-caused hair loss due to the scratching and biting, etc.  Most notable is intense scratching of the neck and behind the ears using their back feet.
• In some cases, there may be GI symptoms like diarrhea, vomiting or constipation.
• Weight loss and reduced appetite.
• Ear infections – chronic or recurrent.

In addition, there can also be scary, severe allergic reactions: Anaphylactic shock requires emergency medical treatment. Fortunately, this is extremely rare.

How Cat Food Allergies are Diagnosed

Your vet will need some help from you to do a proper diagnosis. For instance, you should be prepared to give him/her a full picture of your cat’s health. This is because symptoms for food allergies are similar to other diseases or environmental allergens, (pollen, toxins, etc.).

And you’ll need to provide a good dietary history, including all current and previous foods she has been eating. This would include snacks, treats, supplements, over-the counter preparations, non prescription and prescription medications and toys.

Your vet will then check your cat over thoroughly, running various skin or gastrointestinal tests (depending on the symptoms).

If the vet determines your cat’s misery could be due to a food allergy, s/he may recommend an Elimination Diet Trial. This would involve feeding your darling a strict hypoallergenic diet for 8 to 12 weeks to see if she improves. During this time, only the prescribed food and water can be allowed. No supplements, medications, treats, and snacks can be given. This requires great care and discipline from all members of your household.

This diet would take into account what previous foods she’s been eating. It would feature a novel protein source that your cat has never eaten before (since the allergen culprit is usually meat, fish or chicken).

If your cat is doing better on this diet, you can slowly and systematically start to reintroduce elements of the old diet to see if her symptoms come back. If they recur, you cat is allergic to that particular ingredient and you should avoid it in the future. It is essential that only one new single protein or carbohydrate is reintroduced at a time. Keeping careful records to tract new introductions is essential for a good understanding of the possible allergic response.

There is no current good test to detect a food allergy in your cat other than a food elimination and challenge feeding trial. It’s definitely a process involving trial and error. Be patient – your cat will ultimately thank you!

What’s the Best Cat Food for Cats with Allergies?

The obvious answer is: Something that doesn’t contain any of the food products that cause  an allergic reaction. It’s a matter of managing, rather than treating or curing, the food allergy.

When it comes to cat food for cats with allergies follow these tips:

• Put your cat on a “novel” protein diet (a protein that your cat has never eaten before). This diet may be commercially prepared or home-cooked (using ingredients that humans eat). You should consider buying the best commercial diets from your vet by prescription. Over-the-counter foods that you get at regular stores probably contain common allergens or other extra ingredients that may provoke an allergy.
• Try a hydrolyzed diet for the elimination food trial. This is a prescription food that contains proteins that have been chemically broken down into small pieces (peptides). The process, called hydrolysis, makes the proteins unrecognizable to a cat’s immune system. So it helps reduce or eliminate the allergic reaction.
• If fish is a “novel” protein, fish-based dinners can be the best cat food for cats with allergies. It’s a natural source of Omega-3 fatty acids, which helps with a cat’s skin coat, immune system and heart health.
• Switch to a home-made diet. This is a commitment, as you’ll need to ensure the diet is nutritionally balanced. Use novel proteins and carbohydrates that your kitty has not been exposed to before. Ingredients should be high-quality and human-grade. Rotate ingredients to provide variety and prevent new allergies from developing. And cook all meats thoroughly to kill bacteria and parasites. Be sure to consult your vet to understand what nutrients need to be included.

If your cat’s symptoms are alleviated, any of these diets can be continued indefinitely.

How Do I Help My Cat in the Meantime?

While all this diet testing and eventual diet adoption are happening, your cat may still be scratching up a storm. There are some treatments that can help your cat during the process of eliminating the allergens in his body.

• Your vet might prescribe a low-dose corticosteroid like prednisone to relieve some of the itching.
• Your vet may also consider using Atopica (cyclosporin) to manage her allergies.
• Your cat may have scratched, licked and bitten so much that secondary bacterial or yeast infections have developed. While a vet can prescribe antibiotics, products such as Banixx Pet Care spray work as an antimicrobial and anti-fungal spray that provides sting-free relief for cats suffering from wounds, scratches, fungal infections and more.
• Baths with medicated shampoos such as Vetoquinol and EquiShield® IR Shampoo may also help in some cases.

Finally, we recommend regular follow-ups with your vet to monitor your cat’s progress. Your vet can help you make adjustments to your cat’s diet if needed.

Final Takeaway: How to Keep Your Cat Comfortable with Food Allergy Care

Managing cat food allergies requires lifelong commitment to a strict, controlled diet—meaning no table scraps or unapproved treats. While that’s the challenging part, the good news is that many cats show significant improvement within 12 weeks or less when placed on an appropriate, veterinarian-recommended diet. With the right nutrition, your cat can become comfortable and itch-free again—improving her quality of life and your peace of mind. If you have more questions on managing cat food allergies, call us at 800.786.4751.