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Food Allergies - Topic Overview

A few foods cause most allergies. The protein in a food that causes an allergy is called a food allergen.

  • Milk, eggs, peanuts, tree nuts, fish, shellfish, wheat, and soy cause most problems in children.
  • Milk, peanuts, tree nuts, fish, and shellfish cause most problems in adults.

If you are allergic to one food, you may also be allergic to other foods like it. So if you are allergic to shrimp, you may also be allergic to lobster or crab.

Your doctor will ask questions about your medical history and any family food allergies. And he or she will do a physical exam. Your doctor will also ask what symptoms you have. He or she may want you to write down everything you eat and any reactions you have. Your doctor will consider other possibilities that could be confused with food allergies, such as a food intolerance.

Because food allergies can be confused with other problems, it is important for your doctor to do a test to confirm that you have a food allergy. Your doctor may first start out with either skin testing or a blood test to determine what you are allergic to. But an oral food challenge is the best way to diagnose a food allergy. In an oral food challenge, you will eat a variety of foods that may or may not cause an allergic reaction. Your doctor watches to see if and when a reaction occurs.

A skin prick test can help to find out which foods will cause a reaction. The doctor will put a little bit of liquid on your skin and then prick your skin. The liquid has some of the possible food allergen in it. If your skin swells up like a mosquito bite, your doctor knows that you are allergic to that food. Your doctor may also do blood tests to look for the chemicals in your blood that cause an allergic reaction.

The best treatment is to never eat the foods you are allergic to. Learn to read food labels and spot other names for problem foods. For example, milk may be listed as "caseinate," wheat as "gluten," and peanuts as "hydrolyzed vegetable protein." When you eat out or at other people's houses, ask about the foods you are served.

If you have a history of severe food allergies, your doctor will prescribe an allergy kit that contains epinephrine (say "eh-puh-NEH-fren") and antihistamines. An epinephrine shot can slow down or stop an allergic reaction. Your doctor can teach you how to give yourself the shot.

You can have symptoms again even after you give yourself a shot. So go to the emergency room every time you have a severe reaction. You will need to be watched for several hours after the reaction.

If you have had a serious reaction in the past, your chance of having another one is high. Be prepared.

  • Keep an allergy kit with you at all times.
  • Wear a medical alert bracelet camera.gif to let others know about your food allergy.
  • Check the expiration dates on the medicines in your kit, and replace the medicines as needed.
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WebMD Medical Reference from Healthwise

Last Updated: February 25, 2013
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.
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