10 months ago, my dad started getting these random "reactions" where his lips (mainly his upper lip) would get incredibly swollen. So swollen that it is sausage-like and I cannot even recognize him. It looks very exaggerated, but it would go away after a few days.
At first we thought it might have been a food allergy but he's gone to so many of those tests and nothing's come up. He's avoided foods that he ate prior to getting the swollen lip each time but it's never it. (e.g. one time he got it at night after a lobster meal, so he avoided lobster... but then one time he ate it and there were no problems)... It doesnt seem to be an environmental thing because he's had it at home (pacific northwest) and on trips in north america and asia. It comes up so randomly and quite often but it would go away. It bothers all of us a lot to not know what it is.
He's in his 60s and is retired. High blood pressure sometimes but otherwise very healthy and well and lives a balanced lifestyle.
Would really appreciate anyone who has any ideas / advice / experience / stories / answers. Thank you in advance!! :)