Welcome to NeuroTalk:

I'd like to respond here about body parts swelling up fiercely and going down in a few days...moving around. While I do not have RSD, I have had these swellings, including the abdomen, bladder, and left ankle. My right hand will swell up for no reason, then go away.

In my case it was a reaction to a blood pressure pill...an ACE inhibitor called lisinopril. It was acquired angioedema, + a drug induced lupus, which is now resolving.

Here is a post I made here recently with links to read:
http://neurotalk.psychcentral.com/post967824-161.html

I now have a tentative diagnosis of HAE from my internist and will be going to an immunologist once I am fully recovered from the drug reaction aspect. She believes my attacks of swelling, diagnosis of osteoarthritis, and GI upsets have all now been connected, and the reaction to the ACE inhibitor was some trigger for a worse attack finally.

This diagnosis is elusive and hard to pin down. It has only really been on the books since about 1972. My doctor had a CME last year about it, so is a bit more informed than most.
My problems were always GI spasms and cramping, with some vomiting when I was younger. I still have that, but my ankle is not swelling up so much now that the drug has been stopped.
Some foods trigger it too...mostly citrus, and nightshade veggies.

HAE or acquired angioedema is really thought to be rare, but I suspect more people have it than realize. So I am bringing it up here for you to consider.