http://en.wikipedia.org/wiki/Chronic_cold_urticaria
I was diagnosed in middle skill as basically being allergic to the cold. Normal doctors usually don't know anything about this, but if you go to a specialist who focuses on allergies, they can diagnose you so that you can get the drugs to cancel out the symptoms. I have to use medical grade anti-itch stuff because the stuff available at the store doesn't work on me. I generally just avoid the cold, but if you have to go swimming or something then you want to take some anti-histamine medicine beforehand, otherwise you will have a reaction though out your entire body at once, and it can possibly lead to death if it gets too severe.
I get the same thing. I never used to get it until one day at the beach I got extremely cold and couldn't move even after coming in and lying in the sun. Since then I began to get it in the water starting on the feet and hands and then around my hips and lower back. Then it began to happen when i got cold out of the water. Does muscovado sugars go by any other name? I'm glad to find some other sufferers as I began to worry.
I have a similar reaction, have had on and off for years, never been to the doctor, but in recent years reckon I have pinned down the cause to a certain type of sugar. It seems that if I eat things with muscovado sugar in them (some chocolate drinks, cakes etc) I then for a period of a week or two after my skin will become red and itchy when I get cold. Basically when I get cold I start to itch, then I go red and my skin warms significantly. Am suffering particularly at the moment, so decided to search to see if anyone else had the same problem. Saw your post and thought it was worth mentioning my problem just in case the the underlying cause is the same.