How Do Doctors Test for Food Allergies?

Print this page Bookmark and Share
Parents

How do doctors test for food allergies?
- Debra

Doctors often use a combination of skin testing and blood testing to diagnose a food allergy.

One common skin test is a scratch test. For this test, a doctor or nurse will scratch the skin with a tiny bit of liquid extract of an allergen (such as pollen or food). Allergists usually do skin tests on a person's forearm or back. The allergist then waits 15 minutes or so to see if reddish, raised spots (called wheals) form, indicating an allergy.

If the doctor thinks someone might be allergic to more than one thing — or if it's not clear what's triggering a person's allergy — the allergist will probably skin test for several different allergens at the same time.

When a skin test shows up as positive with a certain food, that only means a person might be allergic to that food. In these cases, doctors may want to do additional testing.

To diagnose a food allergy for certain, an allergist might do a blood test in addition to skin testing. This involves taking a small blood sample to send to a laboratory for analysis. The lab checks the blood for IgE antibodies to specific foods. If enough IgE antibodies to a particular food are in the blood, it's very likely that the person is allergic to it.

If the results of the skin and blood tests are still unclear, though, an allergist might do something called a food challenge. During this test, the person is given gradually increasing amounts of the potential food allergen to eat while the doctor watches for symptoms.

Skin tests may itch for a while. If your child undergoes one, the allergist might give you an antihistamine or steroid cream for your child to use after the test to lessen the itching.

Reviewed by: Steven Dowshen, MD
Date reviewed: May 2015



Related Resources

OrganizationAmerican Academy of Allergy, Asthma, and Immunology The American Academy of Allergy, Asthma, and Immunology offers up-to-date information and a find-an-allergist search tool.
OrganizationAllergy and Asthma Network/Mothers of Asthmatics (AAN-MA) Through education, advocacy, community outreach, and research, AAN-MA hopes to eliminate suffering and fatalities due to asthma and allergies. AAN-MA offers news, drug recall information, tips, and more for treating allergies and asthma. Call: (800) 878-4403
OrganizationFood Allergy Research and Education (FARE) Food Allergy Research & Education (FARE) works on behalf of the 15 million Americans with food allergies, including all those at risk for life-threatening anaphylaxis.
Web SiteFood Allergy Research and Education (FARE) Food Allergy Research & Education (FARE) works on behalf of the 15 million Americans with food allergies, including all those at risk for life-threatening anaphylaxis.


Related Articles

Going to School With Food Allergies With preparation and education, a child with a food allergy can stay safe at school.
Food Allergies Food allergies can cause serious and even deadly reactions in kids, so it's important to know how to feed a child with food allergies and to prevent reactions.
Serious Allergic Reactions (Anaphylaxis) Kids with severe allergies can be at risk for a sudden, serious allergic reaction called anaphylaxis. The good news is it can be prevented and treated.
Milk Allergy Milk allergy can cause serious reactions. Find out how to keep kids safe.
Food Allergies and Food Sensitivities Find more than 30 articles in English and Spanish about all aspects of food allergies in children.
Milk Allergy in Infants Almost all infants are fussy at times. But some are excessively fussy because they have an allergy to the protein in cow's milk, which is the basis for most commercial baby formulas.
If My Child Has Food Allergies, What Should I Look for When Reading Food Labels? Food labels can help you spot allergens your child must avoid. Find out more.
What's the Difference Between a Food Allergy and a Food Intolerance? Food allergies and food intolerances, like lactose intolerance, are not the same. Find out more.
What Is Skin Testing for Allergies? A scratch or skin prick test is a common way doctors find out more about a person's allergies.
How Do Doctors Test for Allergies? Find out what the experts have to say.
All About Allergies Up to 50 million Americans, including millions of kids, have an allergy. Find out how allergies are diagnosed and how to keep them under control.
Allergy Shots Many kids battle allergies year-round, and some can't control their symptoms with medications. For them, allergy shots (or allergen immunotherapy) can be beneficial.
Hives (Urticaria) Has your child broken out in welts? It could be a case of the hives. Learn how to soothe itchy bumps and help your child feel better.
Fish Allergy Fish allergy can cause a serious reaction. Find out how to keep kids safe.
Nut and Peanut Allergy If your child is allergic to nuts or peanuts, it's essential to learn what foods might contain them and how to avoid them.
Egg Allergy Helping your child manage an egg allergy means reading food labels carefully, being aware of what he or she eats, and carrying the right medicines in case of an allergic reaction.




Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor.

© 1995-2016 KidsHealth® All rights reserved.
Images provided by iStock, Getty Images, Corbis, Veer, Science Photo Library, Science Source Images, Shutterstock, and Clipart.com



 

Upcoming Events

The 31st Annual Ghost N Goblins 5k Run and Walk registration. The 5k Run/Walk benefits Dayton Children's Hospital.

Car Seat Safety Check

Car Seat Safety Check

Car Seat Safety Check

View full event calendarView more events...

Health and Safety

Your child's health and safety is our top priority

Accreditations

The Children's Medical Center of Dayton Dayton Children's
The Right Care for the Right Reasons

One Children's Plaza - Dayton, Ohio - 45404-1815
937-641-3000
www.childrensdayton.org