I think there may be connection -- or rather a correlation -- between RSD and infectious disease. Recent research with Vitamin D has shown many if not most of us are deficient and that Vitamin D is necessary for many physiological functions. So, when inflammation is triggered by an injury, isn't it possible that Vitamin D plays a role in turning it off? When we don't have enough Vitamin D to activate the anti-inflammatory compounds in our bodies (like Interleukin-10), then the inflammation continues and spreads throughout the sympathetic nervous system and beyond. In case you are not aware, Vitamin D has been shown to reduce cancer risk as well as bacterial and viral infections and may play a whole host of other roles in the body -- Check out the Vitamin D council website.