It's also called Cholinergic Urticaria. Basically it's a condition where you breakout in hives and start to itch whenever your body gets hot. Doctors aren't sure as to what exactly causes it or how to cure it. Here's an article on it: Cholinergic Urticaria and Chronic Heat Hives - Do You Itch When You Get Hot?
Well funny you posted this as I do. But as part of my *triad* of cold induced hives, heat (or more like sunburn induced hives) and stress induced hives. I've dealt with this mysterious condition since I was 17. I think it has been cultivated from growing up in a stressed out environment that primed my immune system (immuno-globulin e) to be ready to release histamine at a drop of a hat. It sucked, but I got used to it and learned how to ignore the itch. The embarrassing part of the stress induced hives is when some acts overly concerned when you have a case of 'em up to your forehead. I had a really bad case of 'em on 9/11 as my step-mom was in the 7 world trade building and there was a period of time where we weren't sure wtf was happening w/her. One time I had an adverse reaction to medication (sulpha meds.) and I had a massive release of histamine and I almost died (anaphylaxis) I think that the urticaria predisposed my immune system to over react that way. My skin turned ketchup red and swelled in a hivey pattern that joined together. I got shocky and almost had a heart attack. Well the good news here and now at 40 y.o. is that when I moved to a warm climate, my hives drastically reduced. I don't swim in the ocean in the winter here tho, the Caribbean would be better for that. The water here gets too cold. When we go up the volcano here, I do get a minor case of hives for a day. But it's never been very dramatic at all. I think my immune system has backed off and relaxed a bit since I've moved to paradise.
