A food allergy is an adverse or abnormal immune reaction to a food or a food additive.
A few specific foods seem to cause a majority of the food reactions. The most common triggers of a food reaction include:
This condition is more common in young children.
Factors that increase your chance of food allergies include:
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You will be asked about your symptoms and medical history. A physical exam will be done. Food allergies are often diagnosed based on your own observations. It is a good idea to keep a diary of your symptoms. Note when the symptoms occur and what you have eaten.
Tests may include:
You may be asked to go on an elimination diet. This should be done under your doctor's care. You will not eat a suspected food. If your symptoms decrease or go away, your doctor may be able to make a diagnosis. If you eat the food and your symptoms come back, the diagnosis is confirmed. This is most often only done in cases of skin irritation or atopic dermatitis.
A diluted extract of the food will be placed on the skin of your forearm or back. The skin is scratched with a small pick or tiny needles. If there is swelling or redness, an allergic reaction may be present. The doctor will make the diagnosis based on the skin test and your history of symptoms. In rare cases, skin tests can have a severe allergic reaction. This test should only be used under the supervision of a physician or other trained medical personnel. Severe eczema may make this test hard to interpret.
Blood tests (RAST or ELISA) may be ordered. These tests measure the level of food-specific IgE in the blood. IgE is a type of protein that the body produces when it is exposed to something to which it is allergic. The presence of IgE in the blood may indicate an allergy, but is not enough to make a diagnosis.
If you think you've eaten something to which you are allergic and you have difficulty breathing, then call for emergency medical services right away.
To reduce your chances of a food allergy reaction:
If you are diagnosed with a food allergy, follow your doctor's instructions. Consider seeing an allergist—a doctor who specializes in diagnosing and treating allergies.
There is no known way to completely prevent food allergies. If you are a parent, talk to your child's doctor about offering highly allergenic foods, such as tree nuts, peanuts, fish, and shellfish.
American Academy of Allergy, Asthma & Immunology
Food Allergy Research & Education
Allergy Asthma Information Association
Calgary Allergy Network
Boyce JA, Assa'ad A, Burks AW, et al. Guidelines for the diagnosis and management of food allergy in the United States: summary of the NIAID-sponsored expert panel report. Nutr Res. 2011;31(1):61-75.
Food allergy. National Institute of Allergy and Infectious Diseases website. Available at: https://www.niaid.nih.gov/diseases-conditions/food-allergy. Updated March 27, 2017. Accessed October 2, 2017.
Immunoglobulin E (IgE)-mediated food allergy. EBSCO DynaMed Plus website. Available at:http://www.dynamed.com/topics/dmp~AN~T114561/Immunoglobulin-E-IgE-mediated-food-allergy. Updated July 19, 2017. Accessed October 2, 2017.
3/17/2015 DynaMed Plus Systematic Literature Surveillancehttp://www.dynamed.com/topics/dmp~AN~T114561/Immunoglobulin-E-IgE-mediated-food-allergy: Du Toit G, Roberts G, et al. Randomized trial of peanut consumption in infants at risk for peanut allergy. N Engl J Med. Feb 26;372(9):803-813.
Last reviewed September 2018 by EBSCO Medical Review Board Marcin Chwistek, MD Last Updated: 3/17/2015