Id would take her to the vet, my Elvis started pulling his hair out/biting the skin till it bleed/had bald patches after I moved out of home so they said it was stress, he come to live with me about a year later and it stopped........for a while!
It then came back and he looked like a beaten up abandoned cat with hair any fur and red bits
so we had a £600 (insurance!) test done for allergies and it came back with TWO A4 pages of Everything he was allergic to, from carrots to Every type of plant/grass to dust to housefly's t more food!!
He started on injections espically made for him every 2 days to every 4 every 7, then every 2 week, 4 weeks, 6 weeks, 8 weeks based over a year! Now its normally every 3-6months.
Its a extreme case but better safe than sorry!