People can have more than one thing. This is the diagnostic problem.

I have twisted stomach and intestines, which I was born with and is called a "malrotation". I have had huge GI attacks my whole life and in my late 20's I ended up in the hospital for 10 days, with this diagnosis after alot of testing.

I am now just recovering from a huge attack of "something" which included my GI (started there), breathing, burning pain,
joint pain, and puffiness of hands and feet and elsewhere.
I have erythema on my arms neck and face, my lips swelled for 3 days, but hugely. I take Lisinopril for blood pressure, and it appears this whole long miserable attack was perhaps drug induced lupus (which will test with normal ANA pattern and be confusing).

But when I returned from the doctor this time, I started researching bradykinin, because this is what the peptide in the body is that causes all the grief. And that is when I found HAE.
Looking back on my life, I see this pattern of attacks since I was very little. If that is true, adding in the Lisinopril pushed me over the edge finally. I don't get the redness with most of the swelling. But my toes and tips of my fingers started to look very much like some of the RSD pictures on your forum. They also hurt and throbbed in the night.(mostly at that time). I've been off that drug now for a week, and finally I am starting to feel normal. My puffiness was all over, even in the pelvic area! Very painful there, I can tell you!

But all my life I had the vomiting spells, the GI pain, which seemed to pass in a few days. Now that I am older, I've learned to avoid certain triggers, and the vomiting is less. But the lower GI still swells up. I am waiting for the lupus tests, and will ask for the complement tests next, as I really think I had this HAE and it was just not serious enough for me to end up in the ER all the time. It can be very serious when breathing is affected, and the medical sites say 20-30% fatality if the larynx closes up.

It is the ATTACKS, the somewhat normal inbetween times, then the attacks again that seem to be the pattern for HAE.
Just reading your post from RSD seemed familiar to me.

Read the links, and please keep this in mind, for the future. You never know with the rarer syndromes.