Piper also had dry skin. The vet scraped him to make sure no microorganisms were eating his dead skin, then she had this advice: because of Piper's diet changes (they were quick, not gradual, due to him not eating), and the tearless puppy shampoo we were using, she recommended no more diet changes, a prescribed shampoo, and omega 3 oils you can get at the dog store, once a day. It took about 3 weeks, and he was all better! No problems since. Just be gentle and go slowly!
