my Pom is losing his hair.

by Jody
(Brampton, Ont, Canada)

Hello, I have a 3 year old Toy Pomeranian. Since he had returned from the groomers he has some balding on his back just at his tail. he doesn't scratch at all and doesn't seem bothered by it. I brush him 3 times a week to keep his matts away.
Has any one any ideas what could be causing this, and do you think he may need a vet check? It is just at the base where his tail is, at first I thought his tail was rubbing away the hair?
Thanks for your help.
Bailey