Results of food challenge in dogs with cutaneous adverse food reactions

Background Elimination diet trials and food challenge tests remain the gold standard for diagnosing cutaneous adverse food reaction (CAFR) in dogs. However, food challenge tests are difficult to perform owing to a lack of definite information on expected clinical signs and the time frame within which they develop after challenge. Objectives To report the results of the food challenge test carried out in client-owned dogs under observation. Methods and materials A retrospective evaluation of the medical records of dogs presenting with pruritus was performed. Skin infections and/or parasites were treated before inclusion in the study. Dogs that underwent an elimination diet with clinical improvement and relapse with food challenge tests were included in this study. A pruritus Visual Analog scale score was recorded as an index of pruritus before and at the end of the elimination diet trial before challenge. The onset of time to relapse of clinical signs and the body sites affected after food challenge testing were recorded by the owners. Results We examined the medical records of 310 dogs with pruritus. Of these, 46 dogs with a diagnosis of CAFR were enrolled in this study. Significant clinical improvement was observed after the elimination diet trial (P < 0.0001). All dogs exhibited pruritus, and none exhibited anaphylaxis after food challenge testing. Among these dogs, 60.9% developed pruritus within 12 h of food challenge. Notably, 23.9% of the dogs developed pruritus within 3-6 h. The limbs exhibited the highest frequency of pruritus (56.5%), followed by the face (26.1%). Conclusions and clinical relevance This study is the first to report details of the time to onset of clinical signs and body site affected after food challenge testing in dogs. These results will assist veterinarians and dog owners in the decision-making process regarding food challenge testing.