Food allergies in cats are rare. They 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 the more common ‘food intolerance’, which is less severe and causes a totally different physiological process.
The typical symptoms of food allergies include:
- Skin problems – itching and redness, bald areas or actual abrasions of the skin
- Recurrent ear infections
- Increased hair balls
- Gastrointestinal problems including vomiting and diarrhoea
- In rare cases, respiratory problems
If you suspect your cat might have a food allergy, always consult your vet. Never attempt a diet trial yourself, because nutritional problems or deficiencies may result – or your cat might have another problem requiring different treatment.
Diagnosing a food allergy
The most effective method of testing for cat food allergy is an exclusion diet trial. The put onto a special hydrolysed diet (such as PURINA® PRO PLAN® VETERINARY DIETS Feline HA St/Ox Hypoallergenic), where the proteins are so small they cannot cause an allergic reaction. Alternatively, a diet containing proteins and carbohydrates your cat has never eaten before is recommended to demonstrate food intolerance.
If the symptoms disappear or dramatically improve on the new diet, then a food allergy can be confidently diagnosed.
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 4-12 weeks. 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
At the end of the trial, your vet will want to reassess your cat. If no improvement is seen, other diseases can be considered. If there has been an improvement, your vet may recommend gradually 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 – although it is always possible that more than one food type is responsible.
Find the right nutrition for your cat
Once you have identified the ingredients that have caused the problem, you can discuss with your vet which diet is the best choice for your cat’s lifelong health. If your cat’s clinical signs have been severe and the diet has resulted in an improvement, you and your vet might decide to continue feeding the special hydrolysed diet in the long term.