My 1.5 yr old boy, Mickey, started to develop skin/coat problems a few months ago.  I first noticed it when I was patting his back and I felt a patch of his coat had scabs.  His coat was also dry with some flakes.  It doesn't seem to bother him though as he does not seem to scratch or chew on himself any more than the norm.  But the patch of scabs seemed to grow bigger and started to appear in different areas on his back and higher hind legs.  I feed both Mickey and Mushu Blue Buffalo ever since they were puppies.  Mushu's skin and coat look great but not Mickey's.  I read in one of the discussions about people having good experience improving coat problems with grain free dog food such as with Wellness.  So I switched them to Wellness core.  The first few weeks Mickey's coat and skin seem to have improved dramatically.  But it came back again after a couple of months.  I then took him to the vet who prescribed 3 weeks worth of antibiotics.  During the treatment, the patches were visibly getting smaller.  But again, shortly after we finished all the prescribed antibiotics medication, the patches were back again.  Throughout all this, even though Mickey and Mushu eat, sleep, and play together every day, Mushu's coat and skin remained fine so at least I know it is something specific to Mickey.  Does anyone have any experience or suggestion on what I can do next to help improve Mickey's coat and skin condition? I really don't want to subject him to more antiobiotics treatment but I am eager to get rid of these patches of scabs.