A randomized, double-blinded trial to evaluate two therapeutic foods as adjunctive therapies in dogs with environmental and/or food-induced atopic dermatitis.

This study evaluated changes in pruritus, skin lesions, and gastrointestinal signs (G) in dogs fed a positive Control food, Hill's Prescription Diet d/d Potato & Venison (Hill's Pet Nutrition, Topeka, KS, USA) compared to a Test food, Hill's Prescription Diet Derm Complete (Hill's Pet Nutrition, Topeka, KS, USA), over an 8-wk period. We hypothesized that feeding either food would result in improvements in skin lesions and pruritus when compared to baseline while maintaining positive GI and quality of life (QoL) outcomes, but that the Test food would yield superior improvement compared to the positive Control due to its specific immunomodulating components. Thirty-nine client-owned dogs with canine atopic dermatitis were randomly assigned to either the positive Control (n = 20) or Test (n = 19) food to feed strictly for 56 d. Veterinary dermatologists performed physical exams, recorded medication scores, and evaluated skin lesions using the Canine Atopic Dermatitis and Severity Index, 4th iteration (CADESI-4). Pruritus was evaluated by pet owners using a validated Pruritus Visual Analog Scale (PVAS). QoL, stool quality, coat quality, and eating enthusiasm were assessed via owner questionnaires. All other endpoints were analyzed using non-parametric methods. No significant differences were present between the Control and Test groups for any endpoints assessed. No differences in medication scores were observed over time for either the Control (P = 0.356) or Test (P = 0.304) groups. Both groups exhibited improvements in CADESI-4 over time (Control: P < 0.001; Test: P < 0.001). Owner-reported PVAS (Control: P = 1.00; Test: P = 1.00), stool quality (Control: P = 1.00; Test: P = 1.00), coat quality (Control: P = 1.00; Test: P = 0.908), and eating enthusiasm (Control: P = 0.427; Test: P = 0.215) remained stable throughout the study for both groups. Owners of dogs in the Control group had no significant changes (P = 0.518) in their QoL over time, whereas owners of dogs in the Test group had improvements (P = 0.022) in their QoL over time. No differences in pet QoL were observed over time for the Control (P = 0.309) or Test (P = 0.687) groups. These data suggest that feeding either the Test or Control foods results in notable improvements in skin lesions over time. Canine atopic dermatitis requires long-term management using a combination of medication and dietary modifications. These foods may play a positive role as an adjunctive therapy in multimodal management plans.