BACKGROUND: Food allergy is a possible cause of atopic dermatitis (AD) in dogs; it is typically diagnosed following an eight-week elimination diet trial (EDT) and a provocation with the original diet. This lengthy procedure is difficult for owners and its interpretation may be unclear.
HYPOTHESIS/OBJECTIVES: To test the effect of prednisolone used in the first weeks of an EDT in order to reduce the total time period for diagnosis. The goal was to perform food challenges earlier than after the traditionally recommended eight weeks.
ANIMALS: Fifty-three dogs with AD were included in the study.
METHODS AND MATERIALS: All dogs were fed a commercially available extensively hydrolyzed protein-based commercial pet food and treated with prednisolone for at least two weeks to control pruritus and inflammation. Dogs were challenged two weeks after prednisolone finished, provided that no flare had occurred. Dogs with relapsing signs were fed the hydrolyzate for at least eight weeks with or without further prednisolone treatment.
RESULTS: Ten of 53 dogs (19%) had no relapse after two weeks off prednisolone: they were subsequently challenged with their regular food, had a relapse of signs and were diagnosed with a food-induced AD within four to six weeks of starting the EDT. In the other dogs, signs remained uncontrolled without prednisolone or relapsed rapidly after its discontinuation: they were considered nonfood-allergic after an eight week EDT.
CONCLUSION AND CLINICAL IMPORTANCE: This study demonstrates that a shorter EDT is possible if the allergic pruritus and inflammation are initially controlled with a short course of glucocorticoids. This shortened trial is likely to improve owner adherence and facilitate the diagnosis of food allergy.