Definition

A food allergy is an abnormal response to a food or a food additive.

Causes

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.

The most common triggers of a food reaction are:

  • Cow's milk
  • Eggs
  • Peanuts
  • Wheat
  • Soy
  • Fish
  • 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 put you at risk are:

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

Symptoms

Symptoms may be:

  • An itchy skin rash
  • Swelling of the lips, mouth, or throat
  • Coughing or wheezing
  • Shortness of breath
  • Belly cramps
  • Diarrhea
  • Vomiting

Hives
Splotchy body rash -adult

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Diagnosis

You will be asked about your symptoms and health history. 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 that is present when you are exposed to a food
  • An oral food challenge to watch for a reaction to a food that you eat with a healthcare provider present

You may need to see a doctor who treats allergies.

Treatment

Some people may need medical care right away.

A food allergy can be managed. Options are:

Avoid the Food

The best way to manage this allergy is to avoid the allergen, foods that contain it, and foods that may have been around it. Always read food labels. Do this even if you do not think a food has the allergen in it. Most labels will state whether the factory where a food was made also works with the allergen. Always ask for the items in homemade foods to check for the allergen. Ask if the item was made with utensils that have come in contact with the allergen.

Medication

People with a mild reaction may be able to take medicine to ease symptoms. The medicine should only be used if a person is exposed to an allergen by accident. Medicines may be:

  • Antihistamines to decrease swelling and itching
  • Corticosteroids to treat severe swelling and itching

People with severe reactions may need epinephrine. It is injected into the thigh. It needs to be carried at all times.

Prevention

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

RESOURCES:

American Academy of Allergy, Asthma & Immunology
http://www.aaaai.org

Food Allergy Research & Education
https://www.foodallergy.org

CANADIAN RESOURCES:

Allergy Asthma Information Association
http://aaia.ca

Calgary Allergy Network
http://www.calgaryallergy.ca

REFERENCES:

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. Updated October 29, 2018. Accessed September 18, 2019.

Immunoglobulin E (IgE)-mediated food allergy. EBSCO DynaMed website. Available at:https://www.dynamed.com/condition/immunoglobulin-e-ige-mediated-food-allergy. Updated May 14, 2019. Accessed September 18, 2019.

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 2019 by EBSCO Medical Review Board Dianne Rishikof, MS, RDN, LDN, IFNCP  Last Updated: 9/18/2019