my chihuahua

Question
my dog has dry flaky skin she is constanly biting herself on hind legs and she has a rash on her belly she also has smelly ears with brown stuff in them she also gets sores from biting and her ears are red she doesnt seem to be in pain but i know it bothers her .im thinking maybe a yeast infection but not sure .what can it be? i have already tried medicated shampoo and meds for earmites.

Answer
She probably has allergies to something.  She may need some steroid medication to decrease the symptoms and a proper ear diagnosis to get the ears under control.  Many ear infections are the result of an allergy.  If there is a yeast infection or a bacterial infection, then appropriate medication may also be needed to treat these.