Hands Itching, Burning, Swelling. Painful Blisters On Hand. No Help From Cortisone Cream. Suggestions?

Hello - my husband has been having some difficulty with his hands for the last 6 months. First, his hands itch and then they start burning and swell . The next day there appears blisters will pain on the hands. It takes about a week for these blisters to go away. And then a month or so they return for no apparent reason. He has been to a MD and a dermotologist. The MD said it is weird and gave him a prescription for salve and the dermotologist asked if he had insurance and gave him some cortozone cream. No relief....what does a person have to do to get treated. Right now, they are really bad again. We have done some research on the internet and thought maybe its Stevens-Johnson Syndrome but it is just on his hands. Thank you!