There are a few things you can do to help the ears. 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 Canine Probiotics, MSM, 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 dog 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 for a while.
To treat the ears directly I use Zymox otic. It contains enzymes that compete against bacteria and yeast that might be in the ear. If one ear tends to be more affected than the other I like to have a veterinary chiropractor check the spinal alignment. If there is an imbalance in the neck area, the drainage in one of the ears may be reduced and will allow the ear to be more damp which can yield more growth of organisms. Also try to keep the ears dry when bathing or swimming. A little water in the ear can start an ear infection. I put a drying agent in the ear at those times.
Let us know how you progress and please feel free to contact us again if you have any other questions.