kathy
I too ave chronic urticaria and am taking serveral different H1 and H2 histamine blockers. I am now investigating with my dermatologist the chance that I am experiencing an autoimmune reaction to the hormones in my system. My thyroid antibodies were off the chart. I seem to have the most severe attacks just prior to my period and during it. In addition to the thyroid antibodies being so out of kilte, my doctor suspects that I am having progesterone antibody allergies. You may want to investigate this issue with your doctors. I have been in touch with one other sufferer an her antibdies were also te main problem. Good luck.