
Food allergies are the most common feline health issue.
I remember going through this with my cat and it was painful to watch.
In this article, I will give you all the information you need to successfully navigate your way through the tough time.
What Is a Food Allergy or Food Intolerance in Cats?
Food allergies in cats are an adverse reaction that occurs when the cat’s immune system overreacts to a particular food or food additives that it has been previously exposed to.
Food allergies usually occur with ingredients that your cat has ingested in the past and not to entirely new foods that they are trying out.
Reactions that involve the cat’s immune system are called allergies whereas reactions which do not involve the immune system are called food intolerance.
Food allergies are the third most common type of feline allergies after fleas bites and inhaled substances. [1]
What Are the Symptoms of Allergic Reactions in Cats?

There can be several symptoms of food allergies in cats but the most common symptom is persistent itching that doesn’t change with seasons.
Although itching can occur anywhere on the body, in my experience the head and neck are the areas most commonly affected.
The itching that typically signals the presence of a food allergy is caused by the eruption of small, pale, fluid-filled lumps on a cat’s skin, which form in response to the presence of an allergen, a substance to which the animal’s system is abnormally sensitive.
Other symptoms that cats might display due to allergic reactions are
- Scratching
- Overgrooming
- Hair Loss
- Coughing, Sneezing or Wheezing
- Vomiting or Diarrhoea
- Biting
- Ulcerations
What Are The Causes of Food Allergies in Cats?
Food allergies can occur at any age even if your cat has been eating the same food for a long time. Protein is the main culprit that causes the immune system to overreact.
Some of the common causes of allergies in cats are:
- Food: Fish, beef, chicken and milk products are the most common ingredients that cause allergies in cats.
- Age: Food allergies and food intolerance can occur at any life stage
- Breed: Some breeds such as the Siamese have a higher tendency to develop food allergies.
What Foods Are Associated With Food Allergies?
The most common types of foods associated with cat allergies are:
- Fish
- Chicken
- Beef
- Milk products
Some less common allergy causing foods are:
- Wheat
- Corn
- Lamb
- Eggs
- Barley
- Rabbit
How Veterinarians Diagnose Food Allergies in Cats?

The main method veterinarians use to diagnose a food allergy is by using the elimination method. The first thing to do is to remove all symptoms but limiting the cat’s diet and starting them off on hypoallergenic food for around 8 to 12 weeks.
During this time, you should not give your cat any treats or flavoured medications. This will help subdue allergy symptoms and then would begin the process of identifying the exact ingredient your cat is allergic to.
Keep in mind, hypoallergenic food is not meant to be consumed for long periods of time as it doesn’t contain all the nutrients that your cat needs.
After that your vet will start introducing ingredients into your cat’s diet every 2 weeks to specifically identify which ingredient your cat is allergic to. If symptoms appear in the next 14 days, it means your cat is allergic to that particular ingredient.
Your vet might test more ingredients to ensure your cat is not allergic to other ingredients.
Once all the allergy causing ingredients have been identified, the treatment can begin!
How Are Food Allergies in Cats Treated?
Treatment of food allergies in cats include both diet and medication – based on the severity of the symptoms.
In terms of diet, prescription hypoallergenic will be trialled as non-prescription cat food has containment proteins.
As you start the hypoallergenic diet, you might notice that your cat has become more itchy and for which your cat will require symptom specific treatment. Low-dose corticosteroids might be prescribed for symptoms such as itching.
Recovery And Management of Food Allergies in Cats
It takes around 10 weeks after you start your cat on the hypoallergenic diet for the symptoms to subside.
Please ensure that you do not feed your cat any other food during this period.
Food allergies are usually lifelong and you will need to manage them very carefully through an appropriate diet.
You should also avoid giving your cat any supplements as they might cause allergic reactions. Good food has all the nutrients that your cat needs to thrive and there should be no need to give any additional supplements.
We highly recommend the Hills D/D food as the best novel protein food for allergies.
The Bottom Line
Allergies are a painful experience for a cat and problematic for cat parents as well because they need to find a new food that will suit their kitty’s health needs as well as their pallet.
Keep a close eye on your cat when and if you change your cat’s food for any of the symptoms mentioned above.
Always consult your vet if you suspect your cat is having an allergic reaction and follow the diet plans strictly.
FAQ
What is the Most Common Food Allergy in Cats?
Chicken is by far the most common food allergy in cats. Followed by beef, fish and dairy products. Less common sources of food allergies are duck and venison. Cats are rarely allergic to gluten or grains.
What Are The Symptoms Of An Allergic Reaction To A Cat?
The most common symptom of an allergic reaction to a cat is persistent itching as well as scratching, over grooming, hair loss, coughing, sneezing, vomiting and diarrhea.
How Long Does a Food Allergy Reaction Last Cats?
If the allergen is removed the reaction can go away in 2 to 3 days. But since most cat allergies are caused by food and food is essential for survival it can take up to 10 weeks to identify the allergen and remove it from the cat’s diet for the reaction to completely go away.
Is My Cat Suddenly Allergic To Her Food?
Yes, cats can become allergic to a food at any time even if they have been eating it for years. Allergies commonly occur with food that the cats have previously eaten and not with entirely new food.