I'm glad you're heading to the vet soon - he sounds miserable. It could be an allergy - most likely it is either seasonal or environmental - or a food allergy (which is the least common). The first step though is to rule out any pests and/or skin infection/invasion or fungus.
If allergies are diagnosed, you may want to consider Atopica (if you can't prevent exposure to the allergen, that is) - my Marcel does great on it.
If your vet cannot properly diagnose the issue, I can't recommend highly enough that you see a Vet Dermatologist. I had to go that route - and while it's not cheap, it's worth every penny to solve the problem.
__________________ ~ A friend told me I was delusional. I nearly fell off my unicorn. ~
°¨¨¨°ºOº°¨¨¨° Ann | Pfeiffer | Marcel Verdel Purcell | Wylie | Artie °¨¨¨°ºOº°¨¨¨° |