Hello
I have a black toy - is your's white? Mine's never had any skin problems, but sometimes the whites, like Maltese pups, can have skin issues because they are like freckle-faced fair people in that respect - excema, hives, etc. (humans).

Definitely switch the food, science diet isn't any good. Try Solid Gold, California Natural, Canidae, Wellness, Innova, etc. I switched my girl and her tears are less, her coat is much more vibrant and her digestive behavior is very regular. Good luck, and def post a pic!