I would suggest that you try a fish and potato food for at least a month and see if there any improvements.
Try to avoid other foods during that time. Maybe you could use the kibble as treats too. To reduce the symptoms you might try Derma-IonX, which is an oral homeopathic product that stimulates the enzyme systems in the body, which helps reduce itching and inflammation, promotes healing of the skin and helps with assimilation of nutritional components in diet and supplements. The supplements I use along with it include digestive enzymes, probiotics, and fish oil. Together with Derma-IonX it produces a synergistic effect for a faster response. It can also be used topically if there are troublesome spots on the skin. I would also suggest that you give your dog only filtered water for drinking and bathing if your water contains chlorine or fluoride.
Please feel free to contact us again if you have any other questions.