I Have A Beagle-terrior Mix Senior Dog. She Constantly Has

I have a Beagle-terrior mix senior dog. She constantly has yeast in her ears. i have been to the vet a couple of times with her about the problem. Nothing seems to be effective long term. She also has a wart like growth on the opening of her ear. Her ears are stinky most of the time and Itchy. I feel so bad for her. She doesn't like when i clean them. Do you have any suggestions that will help this problem?