<human>: Over the years, this mysterious rash has gotten a little better through the use of anti-histamines, but I still manage to get it in extreme colds and extreme hots. I cannot do any form of exercise, as my skin begins to itch and feel prickly. 

I used to think it was only due to exertion of energy, but then it started happening in the winter for no reason at all. I could just be sitting in the cold and I'd have this rash on my upper arms.

It mostly occurs on my upper/lower arms, thighs, stomach, neck, and chest. I think one thing they called it was Euritikaria(sp?), but I do not feel like I fit that criteria because of the cold factor.

I can't even swim without breaking out.

Can anyone relate to this (shitty) problem that's been hindering my activity for years?

Can you give me the gist of the text in a nutshell?
<bot>: I get a rash from extreme temperatures, and was looking for someone with cures/remedies/someone who can relate.