You might want to look at some of our products to help the skin. DERMA-IONX which is an oral homeopathic product stimulates the enzyme systems in the body which aids the skin and helps with assimilation of nutritional components in diet and supplements. The supplements I use along with it include probiotics and Omega 3,6,9. These supplements together with DERMA-IONX can produce a synergistic response. I would also suggest that you give your dog only filtered water for drinking and bathing if your water contains chlorine or fluoride.
For the dietary modifications a grain free diet with cooling proteins according to Chinese food therapy could be helpful. If your dog is warm and seeks cool places to relax in he might do better with the cooling diet. Fish and turkey are considered to be cooling so would be better choices than chicken or lamb which are warming. Beef is neutral. Of course if your dog has a food sensitivity to a particular food do not give that food.
Also check the coat with a flea comb for any flea debris (dark flecks). Even one flea can start an allergy cascade. Please feel free to contact us again if you have any other questions or to let us know how you are doing.