I’m reading this with some fascination. When I was a kid, I would walk to school in the winter and by the time I got there, my legs, which were covered in woolen tights, would be a mass of huge itchy red welts. I would go to the nurse in the school complaining but they didn’t ask to see my legs, they just called my mother to take me home. Of course, by the time she got there, I would have warmed up and the welts would be gone. She thought I was lying to her and I caught unshirted hell. I can’t remember how long that went on before she finally saw them for herself and took me to a doctor. Who told her I was allergic to cold.
The thing went away after a few years. But I am now struggling to figure out whether I have some kind of autoimmune disease (in the absence of expected lab results) because I’ve developed Raynaud’s and other weird symptoms. Is there a connection between the cold allergy of more than 40 years ago and my weird symptoms now do you think?
I break out in hives if exposed to extreme temps (or mildew, or stress). Cold wind on a warm day or air conditioning after getting very overheated seem to be the worse. I never knew it had a name! I just live with it.
My knowledge of this topic is limited to some recent googling and what I have learned in this thread and the links provided. So with the power invested in me by the State of Wagness, I respond to you.
Raynaud’s is an extreme reaction to cold. Your body responds to cold in the way it should, just that it overdoes it. So capillaries constrict and sink, but they do it to the point where you get apoxia and all the ensuing troubles (like gangrene if it happens for too long).
Cold Urticaria is an allergic reaction (histamine release and all it causes) to cold. The mechanism through which it happens (the point of my OP) is apparently unknown (or at least unknown to respondents to this thread and the authors of the sources I have found).
I’ll join in the WAGing, and toss out a possible mechanism for “cold allergies”. My first response was the same that other posters mentioned – how can an antibody recognize “cold”?
There are whole classes of mutations that render a protein sensitive to heat or cold. In general, the idea is that the mutation makes the protein unstable, so it misfolds or otherwise cannot function outside of a certain range of conditions.
It then might be plausible that some individual has a particular IgE antibody that will bind nonspecifically below a certain temperature. Instead of binding to its “correct” antigen, at low temperatures that antibody will bind to something else that’s present in the body, thus triggering the allergic reaction.