Diagnosis of food allergy in dogs.

The diagnosis of food allergy was confirmed in 51 dogs while the responsiveness to a 60-day home-cooked restricted dietary trial (elimination-diet trial) was evaluated. The primary clinical sign of allergy detected and evaluated in all dogs was persistent and nonseasonally pruritic skin disease. The duration of time between starting the elimination-diet trial and remission of clinical signs was recorded. Dogs were then reexposed to diets that had been fed before testing, and the duration of time before pruritus recurred was recorded. The elapsed time during which dogs were being fed an elimination diet before remission of clinical signs was 1 to 3 weeks in 13 dogs, 4 to 6 weeks in 25 dogs, 7 to 8 weeks in 10 dogs, and 9 to 10 weeks in 3 dogs. Findings indicated that the recommendation of a 3-week elimination-diet trial for diagnosis of food allergy was adequate for only 25% of the dogs. It is recommended that test diets be fed for at least 10 weeks before a food allergy is ruled out.