There can be more than one reason for yeasty ears. Allergies can contribute to moisture in the ear canal which makes it easy for organisms to grow. If the muscles in the neck become real tight, drainage from the ears can be reduced and lead to dampness as well. There are a few things I do to handle chronic ears.
You might want to look at some of our products 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 and helps with assimilation of nutritional components in diet and supplements. The supplements I use along with it include Canine probiotics, vitamin C, 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.
If I need to use an ear product I like Zymox otic. Your veterinarian might carry it. Using these products is a simple and effective way of helping resolve a difficult condition. Having a veterinary chiropractic evaluation could be helpful as well.
Please feel free to contact us again if you have any other questions.