Anyone who has an adverse reaction to something after eating it should see an allergist asap. I ate clam chowder and my mouth broke out in hives. I went to an allergist, I am not allergic to clams or any other shell fish or seafood. The hives were caused by the acidic reaction to the milk and potatoes. I am not allergic to potatoes or milk either. Food allergies take extensive testing and are done in groups, like nuts, seafood, etc. They can't test for everything all at once because they are giving you tiny pricks of what you might be allergic to and that could be deadly. I was breaking out in hives with many foods, it turns out I am allergic to none of them. It's the chemical reaction to different foods interacting with other foods. My next step was to go to an allergist immunologist, was tested for a bunch of things and basically it's just food intolerance but not allergies and it has to do with the way my immune system works. The answer is don't eat two acidic foods together, and I do carry two Epi pens just in case.