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Food Allergy

  • Cynthia M. Johnson, MA
Publication Type:


Food Allergy


A food allergy is when the body's immune system overreacts to a food or a food additive.


A food allergy is when the body mistakes a food as being harmful. This makes the immune system release chemicals into the blood that cause symptoms to happen. Common food allergens are:

  • Cow's milk
  • Eggs
  • Peanuts
  • Wheat
  • Soy
  • Fish and shellfish
  • Tree nuts such as walnuts and pecans
  • Sesame seeds

Risk Factors

A food allergy often starts when a person is a child. It may also start or continue when a person is an adult. Things that may raise the risk are:

  • Other allergies, such as eczema or hay fever
  • Family history of food allergies


Symptoms may be:

  • An itchy skin rash
  • Swelling of the lips, mouth, or throat
  • Coughing or wheezing
  • Shortness of breath
  • Belly cramps
  • Loose stools (poop)
  • Vomiting

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The doctor will ask about symptoms and past health. A physical exam will be done. The allergy can be confirmed with a:

  • Skin prick test—to look for a skin reaction when exposed to a food
  • Blood test—to look for an antibody when a person is exposed to a food
  • Food challenge—to watch for a reaction to the food after eating it, with medical staff present

People with food allergies may see a doctor who treats allergies.


People with severe food reactions may need medical care right away. Medicine will be given to help quickly open airways.

A food allergy can be managed. Options are:


There is no known way to prevent food allergies. Parents should talk to their child's doctor about when to start foods that are often allergens, such as peanuts.

Avoid the Food

The best way to manage this allergy is to avoid the allergen. Other foods that may have been around the allergen can also cause problems. Education about the allergen and food labels can be helpful.





  • Bird JA, Lack G, Perry TT. Clinical management of food allergy. J Allergy Clin Immunol Pract. 2015 Jan-Feb;3(1):1-11.
  • Food allergy. National Institute of Allergy and Infectious Diseases website. Available at: https://www.niaid.nih.gov/diseases-conditions/food-allergy.
  • Immunoglobulin E (IgE)-mediated food allergy. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/immunoglobulin-e-ige-mediated-food-allergy.


  • Dianne Rishikof, MS, RDN, LDN, IFNCP
Last Updated:

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.