Ever seen some salads made at a busy restaurant?

    Grab a handfull of lettuce, grab a handfull of cheese, grab a handfull...

Well, you get the picture. Sometimes the gloves don't change. Sometimes the cheese slops over into the lettuce bin. Sometimes too much lettuce was thrown on the prior salad and it's scooped up and thrown back into the lettuce bin - complete with some (hidden) cheese.

Most of the ingredients you mention look fairly benign. Certainly not protein rich.

I'd go for the cross-contamination as a *very* likely suspect.

Pammi: Doctor, doctor - I had a reaction when I ate a salad at Wendy's
Doctor: So, don't eat a salad at Wendy's

Seriously - you have to take into account the speed and chaos of a fast food place and gauge just how much of a risk it is to eat there. Same with our son's egg allergies and eating brunch somewhere. Just too many eggs flying around the kitchen to risk it.

Want a fast, relatively safe salad? Grab a pre-packaged bag of lettuce from the grocery store.

Hope you recover well (and quickly).

Mark