A food allergy is an adverse immune response to a food protein. Food allergy is distinct from other adverse responses to food, such as food intolerance, pharmacological reactions, and toxin-mediated reactions.

Food allergies occur when your immune system makes a mistake. Normally, your immune system protects you from germs and disease. It does this by making antibodies that help you fight off bacteria, viruses, and other tiny organisms that can make you sick. But if you have a food allergy, your immune system mistakenly treats something in a certain food as if it's really dangerous to you.

The food protein triggering the allergic response is termed a food allergen. It is estimated that up to 12 million Americans have food allergies, and the prevalence is rising. Six to eight percent of children under the age of three have food allergies and nearly four percent of adults have them. Food allergies cause roughly 30,000 emergency room visits and 100 to 200 deaths per year in the United States. The most common food allergies in adults are shellfish, peanuts, tree nuts, fish, and eggs, and the most common food allergies in children are milk, eggs, peanuts, and tree nuts.

Most Common Food Allergies

Information and profiles of the most common food allergies.

Dairy Allergies

Soy Allergies

Egg Allergies

Nut Allergies

Wheat Allergies

Seafood Allergies

In adults, the most common foods to cause allergic reactions include: shellfish such as shrimp, crayfish, lobster, and crab; peanuts, a legume that is one of the chief foods to cause severe anaphylaxis, a sudden drop in blood pressure that can be fatal if not treated quickly; tree nuts such as walnuts; fish; and eggs.

In children, the pattern is somewhat different. The most common food allergens that cause problems in children are eggs, milk, peanuts, soy, and wheat. Adults usually do not lose their allergies, but children can sometimes outgrow them. Children are more likely to outgrow allergies to milk or soy than allergies to peanuts, fish, or shrimp.