Food Allergies in Cats
Could my cat have a food allergy?
Food allergies occur when a cat's immune system reacts to a specific ingredient in its diet, usually a protein source. Food allergies are one of several possible causes of itchy skin in cats, but they are less common than flea allergy and environmental allergies. Cats can develop a food allergy at any age, even if they have eaten the same food for years without any problems.
Food allergies most commonly cause persistent itching and skin disease, although some cats also develop vomiting or diarrhoea. As these signs can have many other causes, your vet will need to investigate to confirm the diagnosis.
Once the offending ingredient has been identified and removed from the diet, most cats can be managed successfully.
Food Allergies in Cats: Symptoms, Treatment and Prevention
The signs of a food allergy usually develop gradually and may include:
- Persistent itching, particularly around the head, face and neck
- Excessive grooming or overgrooming
- Red, inflamed or sore skin
- Recurrent ear infections
- Scabs or skin infections caused by scratching
- Vomiting
The symptoms of food allergies are similar to those caused by a range of other skin conditions, so further investigation is needed to identify the underlying cause.
Arrange an appointment with your vet if your cat has persistent itching, recurrent ear or skin infections, hair loss, or ongoing vomiting or diarrhoea. These signs can have a number of different causes, and early investigation can help identify the underlying problem.
Seek veterinary attention promptly if your cat develops extensive skin wounds, stops eating, becomes lethargic, or has severe or persistent vomiting or diarrhoea. These signs may indicate a more serious condition or secondary infection requiring treatment.
There is no single test that can reliably diagnose a food allergy in cats. Your vet will first rule out other common causes of itching and skin disease, such as fleas, mites, skin infections and environmental allergies.
If a food allergy is suspected, your vet may recommend a strict elimination diet trial. They will advise you on the most appropriate diet for your cat and explain how to carry out the trial correctly. This usually involves feeding a specially selected hypoallergenic or novel protein diet for 8–12 weeks, with no other foods, treats or flavoured medications unless approved by your vet.
If your cat's symptoms improve during the diet trial and return when the original diet is reintroduced, a food allergy is considered confirmed.
The main treatment for food allergies is to permanently avoid the ingredients causing the allergic reaction. Once this has been identified, your cat will need to remain on a suitable diet recommended by your vet.
If your cat has developed secondary skin or ear infections, these may require treatment with medication. Your vet may also prescribe medication to help control itching while the skin heals.
Most cats respond well once the offending ingredient is removed from their diet, although it may take several weeks for the skin to fully recover.
Food allergies cannot usually be prevented, as it is not possible to predict which cats will develop them.
If your cat has been diagnosed with a food allergy, the best way to prevent future flare-ups is to avoid the offending ingredient completely. Feed only the diet recommended by your vet, and avoid treats, table scraps and flavoured medications unless they have been approved.
Carefully checking food labels and ensuring everyone in the household follows the same feeding plan can help prevent accidental exposure.
The outlook for cats with food allergies is excellent, provided the offending ingredient can be identified and avoided.
Most cats experience a significant improvement once they are fed an appropriate diet, although skin inflammation and itching may take several weeks to resolve completely. Lifelong dietary management is usually required, but with good compliance, most cats can lead normal, healthy and comfortable lives.
Written by Gillian Burkhill, Veterinary Surgeon, Animal Trust Vets CIC | Published July 2026 | Review date July 2029 | This advice is for UK pets only and is not a replacement for seeing a vet