A constriction in the throat is serious, in my opinion. I'm guessing, just because it's common, that you might have a citrus fruit allergy. The oils from the juice probably dissolve in the alcohol, which makes them more easily absorbed through the mucous membranes of the throat--so you have a more severe reaction than if you just drank the juice plain.
This is just my guess.
There was a nurse that was a regular that would come in to order deep fried clams even though she was allergic to them. She would put her medicine right on the counter to have it handy. I've read that people can crave that food item to which they are allergic.