That's what a specialized vet (dermatologic issues) at Arrowhead Animal Hospital in Westminster diagnosed our 4-yr-old smooth collie with. Same symptoms you described in your pup, but add incessant shedding. Vet thinks it could be an allergy to beef. He's almost always been on a salmon & sweet potato blend of food. Apoquel didn't seem to do much for him when we tried it, and the Prednisone worked off and on. We started him on Immunotherapy. Unbelievable drug. Forget the name. Works great. $150 injection. We have pet insurance. Thankfully.