When you have a food allergy and you eat that food, your body reacts as if the food is trying to cause harm. It fights back by setting off an allergic reaction. A mild reaction may include a few raised, red, itchy patches of skin (called hives). A severe reaction may cause hives all over, swelling in the throat, trouble breathing, nausea or vomiting, or fainting. This is called anaphylaxis (say "ANN-uh-fuh-LAK-suss"). It can be deadly.
A good way to prevent an allergic reaction is to avoid the foods that cause it. An allergy doctor or a dietitian may be able to help you understand which foods might be okay and what to avoid. Learn what to do if you have a reaction.