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How Food Allergy Testing Exposes Life-Threatening Meals

May 15, 2018


If you’re one of the 15 million Americans living with a food allergy, you know how scary it can be. There’s no way to predict how your body will react when you’re exposed. You might have a mild reaction one time and a severe reaction the next, but food allergy testing helps decrease the fear by exposing meals that could be life-threatening.

Food allergy symptoms can range from mild to severe. They may include:

You may even experience a life-threatening reaction called anaphylaxis that needs to be treated right away. One way to decrease your risk is to carry an epinephrine pen at all times. It can reverse your symptoms in just a few minutes.

Or food allergy testing can teach you what foods to avoid. By knowing what foods are potentially dangerous, you’ll know which ones to stay away from. So, let’s look at food allergy testing, how it’s done, and what it can teach you.

Food Allergy Testing: Skin Prick Test

One of the most accurate ways to conduct food allergy testing is by implementing the skin prick test. Skin prick tests are conducted in a doctor’s office. According to the American College of Allergy, Asthma and Immunology, there are two types.

During the first type of skin test your allergist will number or name multiple spots on your back or forearm with a pen or marker. Each will represent a spot where a drop of a diluted allergen will be pricked on the surface of your skin with a sterile, small probe. Many suspected allergens are tested at the same time, that’s why it’s important to accurately label or number them.

If you are allergic to one of the tests, you will have redness and swelling at the test spot. It will look like a mosquito bite and is called a wheal. The diameter of the wheal and the surrounding “flare” will be measured in millimeters

The test is not painful, but can be uncomfortable. The only side effect is the potential reaction.

Sometimes your doctor will recommend a second type of test. In this type, a small amount of the suspected allergen is injected into the skin of the arm or forearm. They’re called Intradermal injections. They are done by injecting a small amount of allergen just beneath the skin surface. The test is typically done to assess allergies to drugs like penicillin or bee venom.

Food Allergy Testing: Blood Test

Another way food allergy testing is carried out is by getting a blood test. Blood tests measure the presence of IgE antibodies to specific foods. IgE is short for “immunoglobulin E” and is the antibody that triggers food allergy symptoms

Blood tests and skin prick tests will yield a “false positive” result about half the time. This means the test shows positive even though you are not really allergic to the food being tested.

Researchers at Food, Allergy, Research, and Education say this occurs for two reasons:

  • The test may be measuring your response to undigested food proteins. It is possible that after digestion, the food protein that enters your bloodstream is no longer detected by your IgE.
  • The test may be detecting proteins that are similar among foods but do not trigger allergic reactions.

Despite the chance of a false positive result, In the hands of an experienced allergist the results are extremely important and very helpful. Your allergist will compare the results to your medical history, so if your history suggests you’ve had a reaction to peanuts on more than one occasion and your blood test shows a positive reaction to peanut proteins, it’s likely you’re allergic to peanuts.

In this case, your allergist may order additional tests, if necessary.

Food Allergy Testing: Oral Food Testing

A highly accurate food allergy testing is oral food testing. It is typically recommended when a definitive diagnosis can’t be determined. It will take place in your doctor’s office and will be performed by an experienced allergist because it can cause a serious allergic reaction.

You’ll be given small amounts of food you’re suspected of being allergic to. If there’s no reaction, you’ll be given a larger portion. If you show signs of a reaction, the test will be stopped. Most reactions are mild and you’ll be given medication to relieve symptoms.

If you show no signs of a reaction, your allergist will rule out the food.

Living with a food allergy is not easy, but knowing which foods are a threat helps you manage those threats. If you think your child may be allergic to something, talk to your pediatrician. Our guide “From Crib to College: Caring For Your Little Ones” also provides valuable health information for parents. In it you’ll find immunization information, prescription tips and even ways you can help your child overcome anxiety at the doctor’s office.