Cat is after her tail

Question
Hi Doc,
We have a long-haired-hymalian (spelling - sorry) who is about 11 years old.  We live in Florida - Sarasota.  She is an indoor only cat, very playful, very smart - we do not know if we train her or vice-versa.  Since she started her coat change over to summer she has been scratching and really chewing her tail.  We have found NO insects and her skin does not seem to be dry.  Lately she is really going to town on her tail - from stem to stern.  She has Hair-ball dry food from Purina (she likes it) and gets 1/2 can of food once per day.  We even add a little bit of water to that to make sure she get enough water.

Any suggestion as to what possibly could be the problem and would something from a Pet Mart type of store help?

Thanks,
Jim

Answer
I would recommend an application of Advantage from your veterinarian to kill any possible fleas just in case...one flea could have snuck in the house and bit her and she is having a reaction.  It could be a food allergy or obsessive compulsive disorder.  You could try switching her food to Nature's Recipe Rabbit & Rice for 8 weeks as a food trial to see if her skin condition improves in case of a food allergy.  Otherwise, a trip to the vet may be needed especially if her tail is becoming sore.