May 09, 2025
Food allergies affect nearly 6 percent of Americans. Here’s how to know if you have one as well as how to manage it if you do.
A food allergy occurs when your immune system mistakenly thinks that a certain food poses a threat to your body and releases chemicals called histamines to fight it off. These histamines trigger food allergy symptoms, which include itching, swelling, hives, difficulty breathing, abdominal cramps, vomiting, and diarrhea. In severe cases, food allergies can cause anaphylaxis, a life-threatening reaction that requires immediate medical attention.
It's important to know the difference between food allergies and food intolerances. If you’re intolerant to a food, you have trouble digesting it. That can produce symptoms such as bloating and gas, but it doesn’t involve your immune system.
Foods and other substances that cause allergic reactions are called allergens. Just nine foods are responsible for 90 percent of food allergies: Cow milk, eggs, tree nuts, peanuts, shellfish, fish, wheat, soy, and sesame.
Peanuts, tree nuts, fish, and shellfish commonly cause the most severe reactions. People with these allergies must be especially careful not to eat even the tiniest quantities of these foods and, in some cases, cannot even be in the same room without anaphylaxis.
To determine whether you have a food allergy, your health care provider will likely start with a physical and ask about your medical history and the health history of your biological relatives. They also will want to know:
• The foods you think are causing your symptoms
• Whether those symptoms always occur after eating the food
• Whether the food is cooked, raw, or both when symptoms appear
• How much of the food you have to eat for symptoms to occur
• How much time goes by between eating the food and the symptoms appearing
• Any other factors that may contribute to the symptoms
Your health care provider may also perform:
• A skin prick test to determine if a certain food causes an allergic reaction
• A blood test to detect the presence of antibodies that can indicate a food allergy
• An oral food challenge test, in which you slowly eat increasing amounts of a food under medical supervision as they monitor for a reaction
Your doctor may also ask you to keep a food diary and eliminate suspected foods for a couple of weeks before reintroducing them one at a time to track symptoms.
Food allergies can’t be cured, but you can get immunotherapy treatments or injections to reduce your risk of having severe reactions.
For mild symptoms, over-the-counter antihistamines may provide relief. If you’re at risk for anaphylaxis, you should always carry an epinephrine auto-injector or “Epi-pen” and make sure those around you know how to use it during an emergency.
Managing food allergies starts with reading labels. By law, food packaging must list any of the nine major allergens if they’re present. Labels may also include warnings like:
• “May contain” one of those foods
• Is “processed in a facility that also processes” one of those foods
• Is “made on equipment with” one of those foods
The last two warnings address the possibility of cross-contact, which happens when an allergen unintentionally ends up in a product that’s supposed to be safe.
If you live by yourself, you can prevent cross-contact by not having any foods that you’re allergic to in your home. If you live with others and you, or someone else, has food allergies, you should:
• Have separate storage, preparation, and dining areas for foods that are safe for everyone and foods that aren’t.
• Cook safe foods first when you prepare a meal. If you can’t do that, cover the safe foods so unsafe foods don’t splatter onto them.
• Thoroughly wash your hands with soap and water after handling a food to which someone in your home is allergic.
• After every meal, thoroughly clean anything you use to cook or handle a food to which someone in your home is allergic, as well as the surfaces (stovetops, counters, tables) on which you prepare and serve food.
• Avoid sharing foods with others in your household.
To minimize the risk of cross-contact when dining out, call ahead to inform the restaurant about your allergy and ask about cross-contact precautions taken in their kitchen.
Depending on their severity, food allergies can range from mildly annoying to life-threatening. If you suspect you have one, talk to a healthcare provider about testing. Know what foods to avoid and be prepared for emergencies. You also should make sure those close to you know what to do if your food allergies cause you to experience a severe reaction.
