Hello, I'm new to this great forum! I have a 15 yr. old JR and suddenly he is licking the fur from the tops of his paws. His vet is treating him with antibiotic shot and apoquel for itch. This is all new and I want to find the SOURCE not just treat the problem. He is on Iams Senior for years and before that the regular Iams........it seems he is quite old to suddenly develop such and intense itch....suggestions please????