I just went through this w/ my baby !!!!! Hang in there it takes along time. I do believe I medicated her ears for at least 3 months.
At first I thought it was so cute how she was getting a black rim on her ears, never thought it was anything. Then her ears started breaking off and the ear hair on the rims was coming off in bunches !!!!! I was really scared something was seriously wrong....but I found out through a website that this is leather ear, black ear. Note there is only one site that I could find on this. So I started calling vets to find out about it, I must of called at least 15 vets and not one knew anything about it......duh !!!!!!! These are our professionals treating our dogs !!!!! Well anyhow the website said that it is from the cold and it only affect silky yorkies. It said to use lotrimin and tea tree oil and alcohol. So I started cleaning her ears every am w/ alcohol then putting tea tree oil on the rims, and at night I smothered her ears in lotrimin. It started clearing slowly, but it takes along time and alot of persistence.
I also read to leave the hair on the ears to keep them warmer. My baby had her ears shaved and now I am leaving her hair grow.
I BELIEVE SHE GOT THIS AT THE GROOMERS......I do believe it is contagious and now I do all the grooming myself. got myself clippers and a video. It is very easy. Who knows what kind of germs, bacteria, viruses there are in there when they go to a place where thousands of dogs go.
Well good luck, if you need anymore advice...let me know....persistence is the key..........
God Bless