I am having the same problem, i eather get REALLY cold or REALLY hot and sweat with both terribly. My nuero saw me the other day (he deals with my epilepsy) and he saw my arms and saw how purple and red they were and felt them and said they were really cold and was very suprised since it was 80 degreese out. I dont ever have an inbetween anymore its eather hot or cold and i cant find anything to help. He doesnt know anything about RSD, but he defently could tell obvisly somthing isnt rite. but he was going to try and find a dr that might know something about it.