Yelping Madness

Question
I have a Chihuahua, and she is about 10 years old. Recently, she has been yelping (throughout the day) and biting and itching her behind and tail. She has been doing this for a few days now and I don't know what to make of it. I've given her a bath with itching relief shampoo, almost every other day now and she still hasn't gotten better. Does she have inflamation of the skin or might this be more serious??
-Cailin

Answer
Without an examination it is hard for me to diagnose anything on the internet.  If she is biting at the tail area, she may have some type of skin allergy or infection.  Another possibility is that he anal glands are full or infected.  Have your vet check her to see.