Puppy Chow is one of the worst foods. Dogs are carnivores... here are the ingredients for Puppy Chow:
Whole grain corn, corn gluten meal, whole grain wheat, chicken by-product meal, animal fat preserved with mixed-tocopherols (form of Vitamin E), soybean meal, brewers rice, meat and bone meal, beef, pearled barley, sugar, sorbitol, fish oil, calcium phosphate, animal digest, salt, phosphoric acid, potassium chloride, sorbic acid (a preservative), dried peas, dried carrots, L-Lysine monohydrochloride, calcium propionate (a preservative), added color (Red 40, Yellow 5, Blue 2), Vitamin E supplement, choline chloride, brewers dried yeast, zinc sulfate, zinc proteinate, ferrous sulfate, niacin, manganese sulfate, manganese proteinate, Vitamin A supplement, calcium carbonate, DL-Methionine, Vitamin B-12 supplement, calcium pantothenate, copper sulfate, copper proteinate, thiamine mononitrate, garlic oil, pyridoxine hydrochloride, riboflavin supplement, Vitamin D-3 supplement, menadione sodium bisulfite complex (source of Vitamin K activity), calcium iodate, folic acid, biotin, sodium selenite.
G-4037
As you can see, it doesn't contain any actual real meat. It is made of cheap grain fillers, dyes, and sugars (along with menadione which causes death and seizures). Some of the most common allergens in dogs are wheat, corn, beef, and soy (which this food contains).
I recommend a food change. Also, you really should go to the vet...