Severe dog ear trouble, HELP!!!!

Hi everyone-

I really need some help from anyone, please!! Here is our story....we have 2 dogs, Kona and Kelty. They are about 7years old are are lab mixes. They look like sisters but are not from the same litter. We are having the biggest problem with Kona. She is having some issues with her ears. Not in her ears, but at the tips, inside. For about 8 months, she has been getting scabs on the inner tips of her ears. THe scabs will start to heal and then she will scratch them off, it is a vicious cycle. We had an e-collar on her for about 2 weeks and one of her ears healed up, but the other one didn't. This is while she was eating the RX food. We have treid EVERYTHING, from RX food, Science Diet, ZD ultra, to a round of prednazone, to ear drops, and nothing is changing. One of the other issues is that she has some serious fear aggression towards the vet so she won't let the vet get close enough to examine her ears. At first, we thought it was a food allergy, so that is why she ws eating the ZD, but after being on it for 3+ months and no change, we have now decided it is time for a through exam at the vets, which means she will have to be fully sedated. THe vet also mentioned a possible biopsy???

I should mention she is now eating Cal. Natural Lamb and Rice, just becasue i think it is pretty simple.

I will aslo say I have a feeling she might be allergic to potatoes, only becasue the last few foods we have given her that have had potatoes in it, she hasn't cleared up and that was the only link I could find in all the foods.

Does anyone have any experience with this????? I'm really at a loss on what to do, at this poin I think we are willing to try anything, but I am sure the vet visit is a start. Any advice/help is much appreciated!!!

Thanks so much!!

I have a Golden Retriever who is allergic to grass (and anything green outside) and several different foods. We have done prednisone and food elimination. We use stupid boots on the feet when he goes outside. He uses a treadmill for exercise, as it is not worth the hassle to him for a regular walk.
We manage him with doses of benadryl and food that he hasn't yet reacted to. The ears are an ongoing issue - when they flare up, he goes on stronger oral meds and panalog for his ears. I do have a friend whose Goden reacted to the panalog, so watch that too.

Check out allergy shots. The testing is done with a blood sample. The shots do need to be given by a vet, until you reach maintenance. Perhaps a different vet would help with the vet aggression.

I had an severe ear infection after my daughter was born. It was exrremely painful, so I can understand her issues with the vet.