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Food Allergies - Topic Overview

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This topic has general information about food allergies. If you would like more specific information about peanut allergy, see the topic Peanut Allergy.

What is a food allergy?

When you have a food allergy, your body thinks certain foods are trying to harm you. Your body fights back by setting off an allergic reaction. In most cases, the symptoms are mild-a rash, a stuffy nose, or an upset stomach. A mild reaction is no fun, but it isn't dangerous. A serious reaction can be deadly. But quick treatment can stop a dangerous reaction.

Allergies tend to run in families. You are more likely to have a food allergy if other people in your family have allergies like hay fever, asthma, or eczema (atopic dermatitis).

Food allergies are more common in children than adults. Children sometimes outgrow their food allergies, especially allergies to milk, eggs, or soy. But if you develop a food allergy as an adult, you will most likely have it for life.

Food allergy vs. food intolerance

Food intolerances are much more common than food allergies. True food allergies are a reaction to food or food additives by your body's immune system.

Many people think they have a food allergy, but in fact they have a food intolerance. Food intolerance is much more common. It can cause some of the same symptoms as a mild food allergy, like an upset stomach. But a food intolerance does not cause an allergic reaction. A food intolerance can make you feel bad, but it is not dangerous. A serious food allergy can be dangerous.

What are the symptoms?

Food allergies can cause many different symptoms. They can range from mild to serious. If you eat a food you are allergic to:

Your mouth may tingle, and your lips may swell as you start to eat the food.
You may have a stuffy nose, wheeze, or be short of breath when the allergens reach your mouth and lungs.
You may have cramps, an upset stomach, or diarrhea as the food is digested.
You may feel dizzy or lightheaded if your blood pressure drops as the allergens circulate through your bloodstream.
You may have itchy skin with red, raised bumps called hives as the allergens reach your skin.

Kids usually have the same symptoms as adults. But sometimes a small child just cries a lot, vomits, has diarrhea, or does not grow as expected. If your child has these symptoms, see your doctor.

Some people have symptoms after eating even a tiny bit of a problem food. As a rule, the sooner the reaction begins, the worse it will be.

The most severe reaction is called anaphylaxis (say "ANN-uh-fuh-LAK-suss"). It affects your whole body. Anaphylaxis can start within a few minutes to a few hours after you eat the food. And the symptoms can go away and come back hours later. If you have anaphylaxis:

Your throat and tongue may swell quickly.
You may suddenly start wheezing or have trouble breathing.
You may feel sick to your stomach or vomit.
You may feel faint or pass out.

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WebMD Medical Reference from Healthwise

Last Updated: March 23, 2011

This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.