My dog Nakoma has a very similar problem- turns out to be a combination of bacterial and fungal infections. He's an American Eskimo dog.
We have been through two vets, whodid help me figure this out, however, didnot cure this.
So, here's what I am doing, and lordy, I can almost hear some of the replies!
First, he gets bathed every two weeks with a natural shampoo I make, and it contains lavender. Then , He's on a very good and diverse diet, most of which I make. Now here's where I think I may get some flak- he gets garlic in his food twice a day , one week on, 3 days off. Once per week, He gets a micro dusting of turmeric. I also keep trimming his fur, to kerp the sores healing.
He is now getting better, slowly. I think this may take another half year- and yes, he is more than worth it!