itchy puppy...

Question
I have a 4.5 month old Jack Russell Terrier. I got him at 8 weeks.  When I brought him home he had a rash on his belly and was itching. I took him to the vet got his first set of shots and a skin scrapping. I was told to bathe him with dial soap times a week and to put frontline on him "just in case" however no fleas were present. I did but he was still itching...but no rash.  So I took him back to the vet and got another skin scrapping and he was checked with a blacklight. There were no signs of anything. I was given Malaseb shampoo and Miconazole Nitrate spray.  The vet said they would treat him for a fungus just to rule it out but didn't believe it was the cause of his itching. I used them both as directed but the spray made him freak out crying so I quit using it. Then he started rubbing his butt on the ground. I has his anal glands squeezed at the groomers but he continued to do it. He also started to scratch at the corner of his mouth until it bled. He was due for his next set of shots and I thought needed to be checked for worms so I took him back to the vet again. They said that the alcohol in the spray was burning him so I was given ResiZOLE lotion in place of it after yet again another negative skin scrapping. I was told to continue with the shampoo as well. I was also given an antibiotic called cefadroxil drops.  The vet seemed to think he had a bacterial infection of the anal glands that was also infecting his mouth. He seemed to be getting worse even with the antibiotic. He went through his first bottle and was now scratching his inner ears, eyes, mouth, neck, and stomach raw and rubbing his butt on the ground until his tail is raw and licking his butt obsessively. He also rubs his face on the ground. I called the vet and told them he was getting worse and they gave me a refill of the antibiotic. He is just about finished with this bottle (about a day left) and is still really bad. They want me to refill this antibiotic 2 more times...but it doesn't seem to be working at all. I don't know what to do at this point. I have spent hundreds of dollars and still no solution.  I feel so bad for him this has now been going on for months.  He can't even make through sleeping or a play session without scratching, biting, rubbing, or licking something.  Do I see a new vet or is there something I can do at home to help ease his suffering. I have tried shampooing all the carpets and dusting under beds and anything I could think of that might be in the house irritating him.  I also have another dog in the house who is not itching at all so I don't think it is something contagious. Please help...I am so lost!  Thanks.

Answer
This is a toughie.  No wonder it is still in the question pool.  Are you feeding him a common brand of dog chow?  

Dial soap?  Cut out the baths.  Brush him every day with a soft bristled brush.  Try a week or 2 with no baths, nothing to eat except dog chow, and a good brushing every day.  If that doesn't help, see a different vet.