
My old dog has recently had similar, it turned out to be a yeast infection on his skin, the vet prescribed a course of tablets & shampoo to bath him once a week. He improved after the first bath.
The sooner you can get her to the vets & start treatment, the sooner her fur can start growing back.
ETA: the smell & greasy coat is an indication of a skin complaint such as a yeast infection, if not treated a secondry infection can take hold and cause awful itching (which my dog got)