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: Steve Dowshen, MD
Date reviewed: April 2012



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
Web SiteThe Food Allergy and Anaphylaxis Network (FAAN) The FAAN mession is to raise public awareness, provide advocacy and education and to advance research on behavior for all of those affected by food allergies and anaphylaxis.


Related Articles

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.
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.
Egg Allergy Because eggs are used in many of the foods kids eat, an egg allergy can pose many challenges for parents.
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.
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.
How Do Doctors Test for Allergies? Find out what the experts have to say.
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.
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.
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.




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

© 1995-2014 KidsHealth® All rights reserved.
Images provided by iStock, Getty Images, Corbis, Veer, Science Photo Library, Science Source Images, Shutterstock, and Clipart.com



 

Upcoming Events

Sponsored by families with ASD, it's the 10th Annual Autism Friendly Halloween Party

Voyage on the Parkway: a fun event for families with preschool aged children.

Wear a red shirt and join community partners walking from Our Lady of the Rosary School to the Kroc Center

Child car seat safety check by certified technicians

View full event calendarView full event calendar

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