Food allergy in dogs

Food allergy is defined as an immunologically based reaction to food. Terriers may be at greater risk than other breeds for developing food allergy. Whereas food allergy may occur at any time in a dog's life, perhaps a third of affected dogs have an age of onset of 1 year or younger. The most common clinical sign of food allergy is nonseasonal pruritus, which is usually generalized. Pruritus may also be localized on the feet, ears, or perianal area. The most common primary dermatologic lesions are papules and erythema. Reported concurrent gastrointestinal signs among dogs with cutaneous signs of food allergy are rare; however, dogs with both pruritus and gastrointestinal signs typical of colitis have been recently documented. The ideal method of diagnosis is the elimination diet, which should contain one protein and one starch to which the dog has not been previously exposed. The recommended length of the elimination diet is 8 weeks. Persistence of some pruritus at 8 weeks may indicate the need for continuing the diet or the presence of concurrent hypersensitivities. Upon resolution of clinical signs, the dog should be challenged with its regular diet to confirm the diagnosis. The most common proven food allergens in dogs are beef, chicken, milk, eggs, corn, wheat, and soy.