bald spot loosing hair

Question
my poodle has a bald spot and loosing hair. The vet scraped the skin to check for mange it was negative. He prescribed prednisone and griseofulvin but it looks like the baldness is spreading and the meds are not doing anything. Please advise

Answer
Hello Tiki,
There could be several things that might make your dog loose hair in a spot.  If the spot is in a circle, it could be ringworm.  Ringworm is actually a bacteria rather than a parasite so you might ask your Vet about that.  
It could also be an allergic reaction to something that your dog came into contact with.  Try and think if you introduced anything new into your home (such as a new cleaning product, any new furnature, etc) or if you have recently switched your dogs food, as this could trigger a reaction.  Make sure your dog is current on flea treatment because fleas can also cause allergic reactions if your dog is allergic to flea bites and a flea bites your dog.  

If none of these things sound like they fit, you may see if your Vet can check your dog for Thyroid problems.  If your dogs Thyroid is acting up, hair-loss is a key indicator.  

If the hair-lose continues, please feel free to write me again.  
I hope this helps some.  Thanks for using AllExperts.com,
Kim