Can anyone give me any advise on Charlie's skin problems. He scratches constantly, and has allergies. I gave him a bath in vet prescription shampoo last sat. and he is even worse. He is fed natural balance dog food, grain free allergy formula. He doesn't seem to want to walk in the grass so I am beginning to wonder if he can be allergic to grass? He is also shedding buckets of hair. Any advise would be welcome. Thanks.