Oh...I definitely know what you are talking about. My leg gets ice cold from the knee down on my left leg (RSD in my left ankle). To the point where when I was doing pool therapy the floor felt really cold to my right foot and HOT to my left...CRAZY! And I go through periods where I have this more often for longer, and other times where I don't have it for days at a time. But one thing I have noticed is that heat always helps the pain (even if just slightly). I often have my foot elevated with the space heater blowing directly on it. And I have a microwave heat pack that I can wrap around my ankle when I walk (if I can stand the weight of it).

It is definitely one of the stranger symptoms...I mentioned it to a bunch of docs before I finally got to the one who diagnosed me (all the others just said it was probably a circulations thing...morons). When I found out it was a key symptom for the diagnosis I was SO annoyed...