Rat Terrier itching!!!

Question
Hi,
I have a 3 yr old rat terrier.  She has been itching like crazy lately!  She seems to turn all pink on her underside also.  We don't see any fleas on her, so I don't think that is the problem.  I am wondering if she is allergic to something...which I am sure will be difficult to pinpoint.  Do you have any suggestions as to what it could be?  Also, is there anything OTC that can help with her itching?  She has been on oral steroids in the past, which didn't help at all.
Thanks for your time!

Answer
When steroids do not help itching, I always think of food allergies or sarcoptic mange.  I would ask the vet about those possibilities.  Have the dog treated for sarcoptic mange even though your vet does not see any mites on the skin scrapings. For food allergies, a 6-12 week trial with a special hypoallergenic dog food will tell you if that is causing the itching.