Low complements occur in HAE... this is a more likely cause.

Here is some reading for you on this:

http://www.haea.org/patients/what-is-hae/

http://circ.ahajournals.org/content/95/5/1115.full

https://www.karger.com/Article/FullText/368404

If you use an ACE inhibitor for blood pressure, this will increase bradykinin and cause the swellings. People with HAE cannot use this family of drugs.

This condition was officially named in the mid- '70's. Many doctors don't know about it. But some continuing ed seminars are now being brought to some doctors today. My doctor went to one, and that was how I was finally diagnosed.

I had a swollen knee years ago and the orthopedic doctor went to drain it (after an MRI showed no tumor or cysts) and couldn't get the "fluid" out. Now we know why... the fluid was disseminated thru all the cells around and in the knee and there was no excess fluid in the joint space.

The attacks with more normal functions that cycle sound very much like hereitary Angioedema. The bradykinin builds up and then is released to cause swelling and pain, which resolves slowly by itself, until the next attack comes.

Bradykinin is related to serotonin and histamine, but is very different in its own way. Steroids and antihistamines do not work in general on it.

You would most likely find an immunologist more helpful than a rheumatologist.