I also had hives so bad I could not wear my clothes this lasted almost a year. I went to allergy specialist who had me take a shot twice a day said I was allergic to mold and grapefruit. ( I never ate grapefruits lol ) anyway one night I had a bad spell and was rushed to the hospital for my gallbladder. After the surgery I have never had the hives again. and I went to many drs for them .. maybe this is a bodys way of telling you there is something wrong inside. I figured it was its was of releasing poisen from my gallbladder... only my opinion tho and has been fifteen years ago with no hives.