Barbara
I have heard of such a thing with people who are allergic to latex. When latex is used in surgery, and it is in many things, it can cause such reactions. Also, my father developed low thyroid and would often experience hives. It typically happened after a stressful week on the road. Once he came home, or also, if he got a cold, he would get terrible hives. He went to an allergist who told him that he was allergic to cold and flu bacteria, but it wasn't until his company physical that the doctor accurately dianosed my dad's problem of low thyroid. Once diagnosed, he went on a regimen of one small pill a day and he has had no problems since then. That was 40 years ago. So, you may want to have that checked.