My hives began last March 2012. I had hives consistently for about 3 months until I had a course of prednisone which relieved them for about two weeks after I discontinued it. Continued with hives all summer. Took Zyrtec, benedryl and a variety of other anti histamines including pepcid. I used to take SAM-e for a case of clinical depression and finally discontinued it in 2011. I started taking Sam-e in the mornings and by noon my hives started to recede but would come back during the night only to be back full swing in the morning. I started taking another 200 mg of SAM-e at night. No more hives. Have been fully free of hives for about two months.
I would presume everyone has different causes for getting hives. But for me, Sam-e has worked to relieve the the breaking out. I don't yet believe I have gotten to the root cause, but no itching or hives sure has helped.