hot spots, i think it is?

Question
dr.,


my chihuahua has been itching his whole body extremely.  It is to the point where now he has bald spots and irritated skin.  I took him to the vet and they tested for fleas and mites.  But there was no sign of any.  He thought it could be allergies so he gave me benedryl to give him and 3v caps liquid hp skin formula.  It has been more than a week and a half and the problem doesnt seem to be resolving.  What do you think it could be and what would help.  Is it a sign of hot spots?  Would a anti-itch cream work?  Do i need to take him in again? Is there any off the counter products that would help this problem?  

Thanks alot.

Nick Knuth
nick_knuth@yahoo.com  

Answer
Even though there are no fleas or mites seen, often times that is the problem.  Almost 50% of sarcoptic mites causing itching will never be found.  I always treat for mites with a special insecticidal dip in really itchy dogs.  Benadryl will not help dog itchy skin diseases.  For that you need a steroid, which can be given by your vet.