What is a food allergy?

A food allergy is an exaggerated reaction in the body's immune system to something you ate or drank.

Food allergies are more common in young children and in people who suffer from other allergies, such as hay fever and eczema (dry skin rash).

How does it occur?

The most common causes of food allergies are:

• cow's milk
• eggs
• peanuts
• nuts
• seafood, especially shellfish
• wheat
• peas
• beans
• tomatoes
• spices
• fresh fruit.

What are the symptoms?

Reactions are varied and may occur immediately or not for several hours. Symptoms can be mild, or they may be life threatening if breathing problems develop.

Symptoms may include:

• swelling in the lips, face, and/or throat
• tingling in the mouth
• vomiting
• loud sounds in the intestine
• diarrhea
• congestion
• cough
• wheezing
• skin rash or hives.

How is it diagnosed?

Your doctor will ask about your symptoms and the foods that you eat. If your symptoms are not severe, you might be able to find which foods cause them by not eating certain foods for a while. (Examples of foods that often cause allergies are shellfish and nuts.) Then you can carefully try eating these foods one by one to see if your symptoms reappear.

If your symptoms are severe and there is no obvious cause, then it may be possible to have allergy skin tests for common food allergies such as egg, cow's milk, citrus, nuts, and shellfish.

How is it treated?

The only effective treatment is to avoid the food that causes the allergy. The doctor may prescribe antihistamines for you to use as needed. Cortisonelike medicine, which you may use for a short time, may also be prescribed by the doctor. For severe reactions, an injection of epinephrine may be needed.

If you are having food allergy symptoms that are not getting better and you are developing throat tightness or having trouble breathing, call 911 for emergency help.

How long will the effects last?

The effects of the allergic reaction last from several minutes to hours, depending on how much of the food you ate and the intensity of your allergy.

Some food allergies are outgrown while others are lifelong. The vast majority of children who are allergic to milk, eggs, soy, and wheat outgrow their allergies. However, allergies to peanuts, nuts, fish, and shellfish are almost never outgrown.

How can I take care of myself?

Most importantly, follow all of your doctor's instructions.

If you have symptoms of food allergy:

• Allow your body to rest by drinking clear liquids (such as water, juice, tea, bouillon, etc.) frequently during the day.
• Reduce your normal activities until the diarrhea stops.
• If you are nauseated, suck on ice chips.
• After the symptoms subside, you may add cooked cereal, rice, custard, baked potatoes, milk, eggs, and carbonated beverages to your diet.
• Return to your normal diet 2 or 3 days later. Fruit, alcohol, and highly seasoned and spicy foods should be avoided for several more days.

More ways to take care of yourself include:

• Use milk-free substitutes if you are allergic to milk.
• Keep track of all reactions.
• Avoid foods that cause reactions.
• Check the ingredients on food package labels.
• Ask about the ingredients in foods prepared in restaurants when you eat out.

If you tend to have severe food allergy reactions, you should ask your health care provider about carrying medication with you, such as injectable epinephrine, for emergency use.

What can be done to help prevent the symptoms of food allergies?

Avoid foods that bother you. Talk to your doctor if you have severe symptoms; you may be helped by drugs you can carry with you and take when you need them.

Substitute soy-based products or milk-free formula for children who are allergic to milk. Adults with lactose intolerance (hypersensitivity to milk), which causes digestive problems, should avoid milk or use lactose-free products.