Marilyn
I don't know if this was a salad bar type of situation or not; nevertheless some restaurants use BISULFITES to keep the lettuce looking fresh. Bisulfites can cause severe reactiosn in asthmatics; It is also called sodium bisulfite and is used to keep dried fruit(like apricots) from getting dark; Apparently bisulfites are used for some shell fish and it is also found in wine; Bisulfites may or may not be what caused your allergic reaction but you should think about it