I had some neighbors who had a very similar problem. Their collie had severe allergies that made him itch and get skin problems constantly. They finally started bathing him once a day with a very mild, soothing, oatmeal-type shampoo. It helped out a LOT. Nearly every day, I saw them outdoors bathing their collie. I admire their dedication---that's a lot of hair!
Maybe something like that would help Buddy?