there are many things it could be. Did the vet do a skin scraping? That would be the best thing to do, as it could be seborric(sp?) dermatits, ring worm, mange, hot spot, and for sure possible allergies, what are you feeding her? I would first of all assume it is allergies and look into her food, that will cause no harm and possible help. I would then go back to the vet, or another vet, because she should have had more done than the vague explanation you gave, is it itchy for her? Good luck, there will be an easy explanation for this, just have to find it! And a vet shoulda figured it out, how long ago was she at the vet? Has it changed since then? How long has it been the same, or how has it changed? Good luck! you will get lots of help here!
I prefer my people to wear fur..
Gonzaga's Lady Perdita "Lady" CKC Yellow Lab
Adoptee Gucci super fuzzbutt
Adoptee Prada crazy dog extrodinaire
Tickles Tortie cat the owns my daughter