You might want to look at some of our products to help heal the skin. DERMA-IONX which is an oral homeopathic product stimulates the enzyme systems in the body which reduces 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 probiotics and Omega 3,6,9. Together with DERMA-IONX it produces a synergistic effect for a faster response. I would also suggest that you give your cat only filtered water for drinking and bathing if your water contains chlorine or fluoride. For the dietary modifications you might want to try a grain free diet that uses fish or turkey as the protein source if your new diet is not like that.
DEFENDEX shampoo which is nontoxic washes away debris and soothes the skin. However, only try this if you can do it safely for both you and your cat. Using these products can help to resolve a difficult condition. Also keep checking for any signs of fleas. Please feel free to contact us again if you have any other questions.