A food allergy occurs when a cat’s immune system reacts to a component of its food. Food allergy usually causes itchy skin or diarrhea. Food intolerance is a reaction that does not involve the immune system but may cause vomiting, diarrhea or other clinical signs. Any cat at any age may develop a food intolerance.
A cat develops an allergy to a specific ingredient in the diet called an antigen. The most common types of antigens that cause feline food allergy are proteins. Allergy is most likely to develop to the most common proteins a cat eats. Some of us feel that early weaning or early gastrointestinal infection both may be contributing factors to the development of food allergy later in life.
Diagnosis and treatment
Food allergy is diagnosed by feeding a novel and unique diet that your cat has not eaten before for at least six weeks. If skin disease or diarrhea resolves then returns when the former food is fed this confirms true food allergy.
We advise feeding a home cooked or commercial diet consisting of nutrients known not to cause allergy. The processing procedures used to produce commercial cat food may somehow increase the antigenicity of some foods. This may lead to processed food triggering an allergic response while fresh food using the same ingredients does not. Some cat food manufacturers produce hypoallergenic foods with altered antigen size, available from us. The vets and Ashley McManus will give you specific advice. Commercial hypoallergenic diets are available from the London Veterinary Clinic’s on-line shop.