I believe that this phenomenon is perhaps much more common than we believe -- since most of us do not talk about it with our friends, co-workers etc, and we do not go out when we experience the severe facial swelling.
1. At age 44 (about 14 years ago), I had a severe incident of swelling of my
lip and tongue
wife, a physician, gave me a shot of adrenaline that brought down the swelling immediately. Within weeks I had another incident.