If everything has been ruled out and she is just obsessively biting her hair. A little bitter apple spray (I know Petsmart sells it, walmart may) will keep her from chewing. It just taste not so good. I would spray my small garbage can because my Tanjhei would just get all the tissue out and tear it into small pieces. A couple of sprays of bitter apple and she would sniff the garbage and move on.
Walmart.com: Bitter Apple Spray, 8 oz: Dogs