McKesson Clinical Reference Systems: Women's Health Advisor 2002.2
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Food Allergy

What is a food allergy?

A food allergy is an exaggerated reaction in the body's immune system to something you have eaten or drunk.

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 foods that most often cause allergic reactions are:

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

What are the symptoms?

Reactions differ. They may occur right away or not for several hours. Symptoms may be mild, or they might be life threatening if the allergy causes breathing problems.

Symptoms may include:

  • swelling in the lips, face, 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 health care provider will ask about your symptoms and the foods 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 come back.

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. Your health care provider may prescribe antihistamines for you to use as needed. Your provider may also prescribe a type of steroid medicine for you to use for a short time. For severe reactions, you may need a shot of epinephrine.

Your health care provider may recommend that you keep a food diary. This involves recording all the food you eat and when you eat it. You should also record any symptoms you may have.

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 severity of your allergy.

Some food allergies are outgrown while others are lifelong. Most 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 and help prevent the symptoms of food allergies?

  • Most importantly, follow all of your health care provider's instructions.
  • Check the ingredients on food package labels.
  • Substitute soy-based products for milk if you are allergic to milk. Adults with lactose intolerance (hypersensitivity to milk), which causes digestive problems, should avoid milk or use lactose-free products.
  • Keep track of all reactions.
  • Avoid foods that cause reactions.
  • 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 medicine with you, such as injectable epinephrine, for emergency use.

Developed by Phyllis G. Cooper, RN, MN, and McKesson Clinical Reference Systems.
Published by McKesson Clinical Reference Systems.

This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.

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