The gold standard for diagnosing cutaneous adverse food reaction (CAFR) in dogs is a 6–12 week elimination diet trial (EDT) using a limited, hypoallergenic protein source, followed by provocation with the original diet. Diagnosis is confirmed when pruritus returns within 14 days of rechallenge. Frontiers in Ve…+1

Diet selection is the foundation of a successful trial. Both hydrolyzed salmon (HS) and hydrolyzed poultry feather (HPF) diets are validated options — both reduce pruritus scores and dermatitis severity scores during the EDT and are well-tolerated. Frontiers in Ve… Serum food-specific IgG, saliva antibody testing, and intradermal testing are unreliable for diagnosing food allergy in dogs and should not be used to select or exclude proteins. Journal of the…

Over half of dogs with CAFR require more than 4 weeks to show a pruritus visual analog scale (PVAS) decrease ≥2 or any decrease in CADESI-4 score, which means early improvement cannot be used to rule out food allergy, and the full trial duration is necessary in most cases. Frontiers in Ve… A shortened EDT is achievable when antipruritic therapy is used in the initial phase: prednisolone administered for the first 2–3 weeks controls inflammation sufficiently to allow food challenge earlier than the traditional 8 weeks in dogs that remain relapse-free after prednisolone discontinuation. Veterinary Derm…+1

When using the shortened prednisolone-assisted protocol, the diagnostic threshold of one relapse or fewer after prednisolone discontinuation carries a sensitivity of 95% and a specificity of 100% for food-induced atopic dermatitis. Oclacitinib can substitute for prednisolone in this protocol, but at the same threshold of one relapse or fewer, sensitivity drops to 63% while specificity remains 100%. Initial treatment duration (2 vs. 3 weeks) does not influence the outcome. Veterinary Derm… Dogs that never achieve 2 weeks off medication without relapse should complete the full standard 8-week EDT. Veterinary Derm…

The 2023 AAHA guideline specifies the following assessment pathway during the EDT: antipruritic therapy is discontinued at weeks 2–3 of the trial, and pruritus is reassessed at week 4. If the dog remains pruritic at week 4, antipruritic therapy is resumed for 2–3 weeks and the diet is continued for an additional 4 weeks. If the dog is not pruritic at week 4, a food challenge is performed by reintroducing the previous diet. Pruritus returning within 14 days of rechallenge confirms food allergy; if pruritus does not return within 14 days, food allergy is ruled out and atopy should be considered. If pruritus returns after rechallenge and the dog is returned to the elimination diet, antipruritic therapy (oclacitinib or oral steroids) may be restarted for 1–2 weeks. If pruritus does not return a second time within 14 days after that medication course, skin cytology should be rechecked — if no yeast or bacterial infection is identified secondary to the diet challenge, food allergy is ruled out. AAHA Clinical G…

Both hydrolyzed diets also improve clinical signs in dogs diagnosed with atopic dermatitis (AD) without confirmed CAFR, making them useful adjunctive tools in canine AD management beyond their diagnostic role. Frontiers in Ve…

Would you like guidance on how to conduct the food provocation challenge and interpret the rechallenge results?