Food Allergies in Cats

Food allergies in cats are rare and usually involve a reaction to one protein ingredient in a particular food, which triggers an allergic inflammatory response. This is not to be confused with more common ‘food intolerance’ which is less severe and causes a totally different physiological process.

True food allergies can occur at any age but the average age at diagnosis is four to five years. Siamese cats may be at increased risk of developing food allergies. Diagnosis is complex and involves diet trials. There are no specific tests available. Studies have shown the offending proteins often include beef, dairy products and fish. The signs of food allergy include itchy skin and/ or diarrhoea. These are obviously not specific and may indicate another problem. Always consult your vet if you observe these signs in your cat.

Signs of a Cat Food Allergy

Typical symptoms of food allergies include;

  • • Skin problems - itching and redness, bald areas or actual abrasions of the skin.
  • • Recurrent ear infections.
  • • Increase of fur balls.
  • • Gastrointestinal problems including vomiting and diarrhoea.
  • • In rare cases, respiratory problems.

If you suspect your cat may have a food allergy, consult your vet. Never try to treat such a problem yourself; diet trials must be closely supervised by your vet. Nutritional problems or deficiencies may result, or your cat may have another problem requiring different treatment.

Testing for Food Allergies in Cats

The most effective method of testing for cat food intolerance is an exclusion diet trial, where a cat is put onto a special hydrolysed diet where the proteins are so small they cannot (or very rarely) cause an allergic reaction. Alternatively, a diet containing proteins and carbohydrates your cat has never eaten before is recommended. Commercial diets are available, and some vets will advise a diet cooked at home.

The duration of the exclusion diet depends on the type of problem: in cases of skin problems, for example, the special diet generally needs to be maintained for from four to 12 weeks, sometimes longer whereas with gastrointestinal problems an improvement is usually seen more rapidly. This diet must be the only thing the cat eats for the duration of the trial, so no treats are allowed. It can be very difficult to stick to such a diet, especially if you have more than one cat, so be honest if you do slip up, and consult your vet if your cat won’t eat the new diet.

After the trial period

Once your cat has finished the trial period, it should be re-assessed by your veterinary surgeon. If no improvement has been noted, investigations into other diseases should be undertaken. If there has been an improvement then your vet will advise you on the next step. This will depend on your cat’s specific problems and may involve reintroducing proteins to the diet and monitoring for a reaction.

If the symptoms return when a food is reintroduced, you may have found the cause. Remember, there may be more than one food type responsible. In some cases if your cat’s clinical signs have been severe, and the diet that has resulted in an improvement is complete and nutritionally balanced, owners and vets may decide to continue feeding that diet in the longer term without attempting to find the specific cause of the allergy. The process requires time and patience and your cat may need to be referred to a veterinary specialist to oversee the diet trial.

How to tell if your cat has an allergy

Cat diarrhoea: what you can do