DERMA-IONX can be helpful for a variety of skin conditions. It is an oral homeopathic product which stimulates the enzyme systems in the body that aid the skin and helps with assimilation of nutritional components in diet and supplements. What sets it apart from most homeopathics is that it is in an oligotherapeutic mineral base which has had a charge added to it.
Initially I would give a half dose of DERMA-IONX on the breakfast and supper food. After there are signs of improvement you can give a whole dose once a day. I would also give Probiotics to aid digestion. OMEGA 3,6,9 is soothing, reduces irritation, and improves coat quality. Vitamin C and quercetin can have an antihistamine effect.
The water you give should be filtered if it contains chlorine. Chlorine is not good for the intestinal flora. Diet can also influence the body. Sometimes the flavor even makes a difference. I would choose a grain free food that uses fish or turkey as the protein since these are considered to be cooling for too much internal heat according to Chinese food therapy. Beef is neutral. Chicken, lamb, and venison are warming and so I avoid these especially in the summer. If your pet is allergic to a protein do not use it even it has the correct thermal property. I tend to use cooling or neutral foods during the summer and warming foods during the cold months for my healthy pets.
If you bathe your dog, I would try DEFENDEX shampoo. It is soothing for the skin and the essential oils are helpful.
Please keep us updated so we can help guide you.