Did you know that as many as 2 million kids and teens in the United States have food allergies?

Allergies to food can be a nuisance, and for some people they are very serious and even dangerous. Knowing what to expect and how to deal with food allergies can make a big difference in preventing someone from becoming very sick.

What Happens in the Body
Food allergies happen when the body has an abnormal reaction to certain foods or food components.

They occur when a person's body begins to treat a certain food (like eggs, peanuts, or strawberries) as an invader (or allergen) that it must protect against. In response, the body then creates IgE antibodies (the type of antibodies involved in allergic reactions) against this food.

Antibodies are special proteins the body makes that work to recognize a specific substance if the body starts seeing that substance as harmful or foreign. Substances that people are allergic to and make antibodies against include germs, medications, certain detergents or perfumes, the venom from bee stings, metals that are used in inexpensive jewelry, and in some cases, certain foods.

Once antibodies are made against a certain food, they will instantly recognize if that food is eaten and enters the digestive tract. In severe food allergies, reactions can occur even if that food is simply touched or if particles of it are breathed in through the nose.

So the next time that same food is eaten, IgE antibodies against that food are activated. Those antibodies then stimulate mast cells, which are allergy cells in the body that release chemicals like histamine into the bloodstream in response to an allergic reaction. The release of histamine in the body can lead to symptoms like itchy skin and rashes, hives (red bumps on the skin), or in more severe cases, difficulty breathing.

Other symptoms of food allergies include:

• swelling in the throat or other parts of the body
• abdominal pain
• eczema of the skin
• dizziness
• diarrhea or vomiting
• wheezing

Sometimes a person's reaction to a food allergy can be much more serious. For these people, eating a food or food component that they're allergic to can be life-threatening. A life-threatening allergic reaction can make someone unable to breathe, cause a dangerous drop in blood pressure, and decrease blood flow in the body, especially to the brain, heart, and lungs. This is called anaphylaxis - and allergies that lead to anaphylaxis are called anaphylactic allergies.

Severe food allergies - to nuts and peanuts, in particular - sometimes cause anaphylaxis.

People who have anaphylactic food allergies might also have seizures, experience a drop in heart rate (because their bodies go into shock), or become unconscious as blood flow to the brain decreases. Symptoms of anaphylaxis can happen quickly, and without medical treatment can cause death.

Immediate emergency treatment, including medications (such as epinephrine) that increase the heart rate and blood pressure, is needed to control any kind of severe allergic reaction. If you (or anyone else you know) have a severe food allergy and accidentally touch or eat that food and start to have a reaction, you should call 911 or immediately go to the nearest emergency room.

• Heredity influences whether a person will have food allergies - if one of your parents has a particular food allergy, you're about twice as likely to have one.
• The most common foods that cause allergies are milk, eggs, wheat, soy, peanuts, tree nuts, shellfish, and fish.
• People often confuse food allergies with food intolerance (like lactose intolerance or MSG intolerance) because they can cause similar symptoms. But food intolerance doesn't involve the immune system, and when a person has a food intolerance, he or she can usually eat small amounts of the particular food without having any symptoms. Although food intolerances can be unpleasant, they are rarely dangerous.
• Kids and teens with certain food allergies, such as allergies to eggs, have a good chance of outgrowing them as adults.

If you think that you might be allergic to a certain food, don't decide for yourself to eliminate that food from your diet. Go to your doctor and have it checked out. Your doctor will make a diagnosis and recommend the best course of action for you.

Testing, Testing
There are three basic methods that doctors can use to diagnose food allergies:

1. Elimination diet: through this method, suspicious foods are removed temporarily from your regular diet. Then (under the direction of your doctor, of course) they are slowly reintroduced one at a time.
2. Skin test: the easiest and fastest method, this test involves your skin being pricked just enough with a tiny needle that a small amount of liquid extract from the food being tested enters your body. If a reaction occurs, like itching, redness, or bumps, the test is considered positive for an allergic reaction.
3. RAST test: With the RAST test, a sample of blood is drawn and taken to a lab where it is mixed with food extracts. If antibodies to the food are found, you have an allergy.

Dealing With Food Allergies
Avoiding the food or foods that cause allergic reactions is the best method of treatment for a food allergy. If you've just found out that you have a food allergy, it will be helpful to start finding alternatives to the food you can no longer eat.

For example, if you're allergic to eggs, find commercial egg substitutes that substitute other forms of proteins. Or, if you're allergic to milk, make sure to eat other good sources of calcium, like broccoli or spinach. Your doctor or allergist or a registered dietitian can help you to plan a healthy diet that includes the nutrients your body needs.

If you have food allergies of any kind, always remember to read food labels. It's very important to be informed about all the ingredients found in any foods that you eat. Remember that labels may be misleading because certain food products can be listed in more than one way. For example, if you have a peanut allergy, you'll need to watch out for foods that contain "hydrolyzed vegetable protein" or "ground nuts," which may contain peanuts. Be sure to ask your doctor or allergist for more information.

When you eat at restaurants, always ask the waiter if any of the foods contain the food to which you're allergic. If you're looking for meal ideas, check out the recipes from the Food Allergy Network, which include foods like apple fritters that eliminate many ingredients that may cause allergies.

If you have severe food allergies or severe allergic reactions of any kind, your doctor will probably recommend that you keep a Med-Alert ID card in your wallet or wear a Med-Alert bracelet that will clearly state your allergies in case of an emergency.

You should also carry an epinephrine kit with you at all times if you have severe food allergies. An epinephrine kit is a single dose of epinephrine (also known as adrenaline) contained in a form that looks like a pen, which can be self-injected as a shot if you come in contact with something to which you are known to be severely allergic. Any teen with known severe allergic reactions, especially those that could lead to anaphylaxis, should also have an EpiPen at home and at school. Talk to your doctor or allergist about getting and properly using an EpiPen.

Reviewed by: Kim Rutherford, MD
Date reviewed: October 2001

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