Dog food allergy is a non-seasonal allergy characterised by pruritus and strong skin lesions similar to those seen in canine atopic dermatitis. Dog food allergy often occurs suddenly after months or even years of eating the usual food. The itching may affect the whole body or be limited to certain areas (ears, face, fingers, armpits, groin, abdomen and perianal area). Otitis externa may be the only visible clinical sign in the dog. Another important sign is an inflammation of the anus margin: anitis. In dogs, food allergy may be accompanied by gastrointestinal signs (diarrhoea, vomiting).
The foods most commonly associated with food allergy vary according to dietary habits, but the main allergens are meats (beef, lamb, chicken, eggs, soy, dairy products and wheat).
The only reliable method of diagnosing food allergy is a strict and exclusive avoidance diet (either household or commercial with selected or highly hydrolysed proteins) lasting +/- 8 weeks. It consists of changing the dog's usual diet for a food that it would never have encountered and to which it should not be sensitised. The diagnosis will only be certified after a systematic reintroduction of different proteins to establish their allergenic power.
A new tool has recently been developed to help the veterinarian choose the ideal diet for the diagnosis: the Cyno-DIAL® test. It is carried out by taking blood samples and is based on a molecular biology method: the immunoblot. This serum test detects the presence of IgE antibodies specific to each allergenic protein (sensitisation) contained in the various food preparations.