The foods that most commonly cause allergic reactions are known as the "big nine" allergens. These include:
- Milk
- Eggs
- Fish
- Crustacean shellfish (such as crab, lobster, shrimp)
- Tree nuts (like almonds, walnuts, pecans)
- Peanuts
- Wheat
- Soybeans
- Sesame
Together, these nine foods account for about 90% of all food allergies. Children most commonly experience allergies to peanuts, milk, soybean, tree nuts, eggs, and wheat, while adults more often react to tree nuts, peanuts, fish, and shellfish. Some allergies, such as milk and egg allergies, are often outgrown during childhood, whereas others such as peanut and tree nut allergies tend to be lifelong. Sesame was recognized as the ninth major allergen in the US starting in 2023, meaning it must be specifically labeled on food products.
