It’s called idiopathic cold induced urticaria

Aka random allergy to the cold.

Had the pain, hives, and if left in temps too long would go into anaphylaxis shock.

I’ll respond later as I need to sleep right now but for a glimmer of hope - if you weren’t born with it there’s a 50/50 chance it’ll go away just as it came on. I lucked out in that 50% where it went away after my immune system got itself back in working order. It all started with Mono and then the H1N1 virus. Wiped out my system.

It’s rare enough that my case is still referenced in the Uni hospital allergy clinic apparently.

Like I said I’ll respond more once I wake up.