Hi,
I'm sorry to hear your boy is suffering so badly. Have you tried some benadryl, it can help some with the itching. You can use the OTC type, the vet can tell you what dosage to use. An oatmeal bath can be soothing when your dog has skin problems.
We've had another dog who is highly allergic to a number of foods, we tried Solid Gold "Holistique Blendz" and it worked well when he had a very bad flare (we were able to figure out that chicken, turkey and beef were the sources of his problem - ironically, he can eat a bison based kibble with no problem). It uses only fish as the protein source, carbs are things like oatmeal and there are stores in Oklahoma that carry it, website with store locator can be found at:
www.solidgoldhealth.com
Once our allergic dog's skin healed we slowly began to transition back to a kibble with a bit of a higher protein level since the Holistique blend is about 18% which was a bit low for a dog with his activity level.
I've heard very good things about the "Simple Solutions" formulas that Wellness makes too. Since we have the skin problems under control now, we're not going to try it to minimize sensitizing him to any other ingredients.
Hope this helps, let us know how it goes,
Penny