Dogs with skin conditions or food sensitivities also need an occasional treat. Hill's, nutritionists and veterinarians have developed special treats for dogs on Prescription Diet® d/d® Canine, Prescription Diet® z/d® Canine, Prescription Diet® i/d® Canine, Prescription Diet® i/d® Sensitive Canine And Prescription Diet® Derm Defense dog foods. This product requires a veterinary prescription.