Bichon Frise skin care

Question
Our 4 year old Bichon practically chews his hind quarters off every time he gets groomed or bathed. He did not start this until we moved to New Mexico. We have changed his diet to a hypo-allergenic food and tried a million different shampoos. Our groomer has done the same. Regardless, he still just chews and scratches until he has no more fur and open sores. He is quite healthy otherwise. This lasts for about 4 weeks after grooming/bathing and then it subsides. HELP!  

Answer
He may be having an allergic reaction to something.  If it occurs after a shampoo, it could be the shampoo.  I would recommend that you get a hypoallergenic shampoo like Dermapet's Conditioning shampoo (www.dermapet.com), which is made from only vegetable oils with no extraneous animal fat or protein. It is the animal fat and protein that most dogs that are allergic to shampoos contain.  You might also ask the vet for some steroids, like prednisone, to use before the grooming to prevent the allergic reaction.