I am experiencing the same thing. Since it occurs every time after eating I assume food allergy. The allergist found none. I had an episode Sat night that benedryl did not help at all. It stayed swollen from Sat night into the day Sunday. Since the swelling is gone I still feel awful. I have appointment with family dr tomorrow.
We plan to go to a remote fishing camp in Canada early Sept. I really need to figure out what is causing this.
I had Chinese box dinner once, breakfast food - some red spices on the potatoes, the restaurant said it just listed spices - not specific, Hamburger and chips, breakfast food sausage had spices. I would like to hear if you get a diagnosis.