Had a long talk with the vet yesterday, she's got a lot of horse sense.
The last couple of days, the dog has been reverse sneezing quite a bit, eyes are tearing up. It's an allergy, gave him some plain old reactine and and it cleared up nicely.
Anyhow, while we were going through all the trials and such with him, there was a big thing missing - the thyroid wasn't being treated. Now that his T4 levels are good, we still have issues and I have to accept the fact that it's an allergy or a reaction to something. The thyroid being out of whack will cause his immune system to be overactive.
So it appears we have environmental - could be dust (we live in a dust bowl), dust mites etc but it really matters not how clean a place is, can't get rid of them. But something is going on internally creating the scratching.
Throw me some ideas of what else to try.