How Else Can Chronic Hives With Itching Be Treated?

I have chronic hives. Ten years worth, out breaks can last a week to over a year. I have been tested for everything the doctors can think of, including cancer, std's, thyroid. The only relief I get is when I am on steriods, min. 10mg twice a day. Currently on zyrtic once a day, xyal once a day, singular once a day and zantac twice a day. Even with all these drugs, nothing is helping. Rash is over entire body. Is their something different we can do to relive the rash and itching. At this point I doubt the cause will ever be discovered.