Milo had it when he was around 10 years old. He had a nasty ear mite infection that got worse and caused it. He was on antibiotics and prednisolone, and the infection cleared, but it took about three weeks. Vet was thinking about ear oblation, yikes, but fortunately it didn't get that far. However, he lost his ear drums and over the next few months went deaf. For the rest of his life (he lived til 15) we had a strict ear cleaning and steroid regime, drops every day, and he had no further trouble. We watched his ears like a hawk, he had narrow ear canals (so do I actuall).
Maybe Laurie needs a longer course of treatment, to really knock it on the head. Milo certainly did, it did not clear up in a week. Hope she recovers soon, it's awful seeing them like that. Ear pain is the absolute pits.
Lesley