Raw is a great idea but you probally dont have to go that far, science diet densitive skin is absolutely awful for food allergies out of the forst 8 ingredients 6 of them are very bad.
SCIENCE DIET SENSITIVE SKIN: Brewers Rice, Whole Grain Corn, Corn Gluten Meal, Pork Meal, Dried Egg Product, Soybean Oil, Flaxseed, Chicken Liver Flavor, Animal Fat (preserved with mixed tocopherols and citric acid), Lactic Acid, Potassium Chloride, L-Lysine, Iodized Salt, DL-Methionine, Calcium Carbonate, vitamins (L-Ascorbyl-2-Polyphosphate (source of vitamin C), Vitamin E Supplement, Niacin, Thiamine Mononitrate, Vitamin A Supplement, Calcium Pantothenate, Biotin, Vitamin B12 Supplement, Pyridoxine Hydrochloride, Riboflavin, Folic Acid, Vitamin D3 Supplement), Choline Chloride, Vitamin E Supplement, L-Tryptophan, minerals (Ferrous Sulfate, Zinc Oxide, Copper Sulfate, Manganous Oxide, Calcium Iodate, Sodium Selenite), Mixed Tocopherols (a preservative), Citric Acid (a preservative), Taurine, Phosphoric Acid, Beta-carotene, Rosemary Extract
find yourself a good grain free food with no chicken, and make sure all his treats are grain free and chicken free as well. which means NO bread. and if you can find a salmon based one the oils will make a huge difference.