Food Allergies? Shellfish, but not ALL shellfish!?

I don't believe this has anything to do with mercury and has a lot to do with your body's tolerance for scallops. It also might have to do with how much er or other seasoning was on the scallops that gave you the symptoms that you had. When you have a food intolerance like this, you just avoid eating that food again. Maybe they were past their prime and you got a mild case of food poisoning. It would be difficult to tell what the exact reason would be for your reaction to scallops. Just avoid them in the future. Without trying clams or oysters, it also would be difficult to tell if a similar reaction will occur. It is a trial and error thing. Without hives, swelling, etc. this was not an allergic reaction, only an intolerance.