Food Allergies Causes, Symptoms, and Testing

What is a food allergy?

A food allergy is a condition in which the body’s immune system abnormally reacts to something typically harmless to most people, such as the proteins in milk or eggs. Food allergies are a growing, serious public health problem that affects both children and adults. Globally, as many as 250 million people may suffer from food allergies with most people allergic to one to three foods.1,2 Although more than 170 foods have been identified as triggers of food allergy, eight allergen groups account for 90 percent of food allergies.2,3 Food allergies have a wide variety of symptoms, which may involve the skin, gastrointestinal tract, cardiovascular system, and respiratory tract.

Food Allergy or Food Intolerance?

It's vital to identify underlying allergic triggers. Get answers with a blood test.

Common Food Allergens


Click on a food allergen to learn more about the specific allergy, including where it can be found, common symptoms, testing information, allergy management, and symptom relief.


Tree Nut
Fruits and Vegetables
Seafood and Shellfish

Are you a healthcare provider looking for a comprehensive list of food allergens and associated symptoms? 

Explore our fact sheets, an easily sharable, patient-friendly resource that includes cross reactivities, component names, and management plans.

Food Allergy Symptoms

Common food allergy symptoms include:

  • Gastrointestinal symptoms (e.g., stomach pain, diarrhea, nausea, vomiting) 
  • Mild wheezing or coughing 
  • Itching or tingling mouth, lips, or throat  
  • Fatigue
  • Urticaria (rash/hives) 
  • Failure to thrive 
  • Intense itching 
  • Facial edema (swelling)
  • Feeling very hot or very cold 
  • Rising anxiety
  • Pale or flushed appearance  
  • Dyspnea (i.e., difficult or labored breathing)
  • Hoarseness  
  • Croupy/choking cough 
  • Very pale/cyanotic lips  
  • Unresponsiveness 
  • Circulatory collapse 

Use our symptom tracker to generate a comprehensive profile of your symptom history. Print, scan, or download your results, and review them with your healthcare provider to decide if a specific IgE blood test is right for you.

Anaphylaxis is a rare, but serious, life-threatening allergic reaction. Symptoms of anaphylaxis may include: Loss of consciousness, a drop in blood pressure, and severe shortness of breath. Anyone experiencing anaphylaxis symptoms should call his or her local emergency number immediately.

Milk, egg, and peanut contribute to the highest number of allergic reactions in children—while peanuts, tree nuts, and seafood are the top contributing allergens in adults and teens.2,3

Frequently Asked Questions About Food Allergies 

While a food allergy and food intolerance have many similar symptoms, they’re not the same thing, and the differences between the two are important. Both conditions usually involve the digestive tract, with uncomfortable symptoms such as bloating and cramping. But for food allergy, reactions can potentially be life-threatening. Because an allergic reaction to food can be so serious and severe, it is important to find out if the reaction was caused by intolerance or by an allergy in order to decide on appropriate management. Read more about the differences between food allergy and food intolerance.

Yes, adults can develop food allergies. If an adult suspects he or she has a food allergy, it is important to talk to a healthcare provider and get tested to confirm the diagnosis.

Food allergies are a growing problem among infants and children.

  • Approximately 40 percent of infants and young children with moderate to severe eczema suffer from food allergies, with eggs, cow's milk, soy, and wheat accounting for the majority of allergenic foods.1,2,5
  • About 40 to 60 percent of children with an allergy to eggs or milk will develop asthma, and 30 to 55 percent will develop allergic rhinitis.2

Fortunately, the majority of children with an egg or milk allergy will outgrow it by age 5.2 In the meantime, though, children allergic to certain foods often experience a diminished quality of life. This is often due to:6,7

  • Social isolation as a result of food restrictions.
  • Anxiety among children and parents regarding school attendance and social events.
  • Avoidance of major foods, which can lead to malnutrition and a failure to thrive.8

For these reasons, early identification and avoidance of the allergenic foods are critical.

Food allergy reactions primarily occur via ingestion. Reactions to allergens can occur when the allergen comes into contact with your mucus membranes, which line the mouth, eyes, and nose. If you are in the same room as your food allergen and you happen to get some of that allergen on yourself, you can have an allergic reaction by touching your mouth, eyes, or nose. Some allergens can also become airborne when cooking. Shellfish is a good example of an allergen whose proteins can become airborne when cooking.9 If the allergens land on the mouth, eyes, and nose, they can trigger an allergic reaction.

Pollen Food Allergy Syndrome (PFAS), also known as Oral Allergy Syndrome (OAS), is an allergic reaction that typically occurs after a person who is sensitive to pollen eats certain foods.8 PFAS is possibly the most common food allergy in adults, with up to 60 percent of patients allergic to pollen being affected.

Food Allergy Testing and Management  

Because an allergic reaction to food can be so serious and severe, it is important to find out if a reaction was caused by an intolerance or by an allergy in order to decide on appropriate management. 

If food allergies are the suspected cause of symptoms, it’s important to consult with a healthcare provider to determine if testing for allergies is warranted or if symptoms may be caused by something else.

A blood test—together with an allergy-focused medical history—may help identify underlying allergen triggers. 

A blood test—together with an allergy-focused medical history—may help identify underlying allergen triggers. 

A diagnosis, followed by counseling and advice based on test results, can help to reduce the incidence of adverse reactions and the unnecessary exclusion of foods that should be eaten as part of a normal, healthy diet.1,11

How is a food allergy diagnosed?

Diagnosing food allergy starts with:

1)  A physical examination  
2)  A food allergy-focused patient (medical) history2,11

Goals of a medical history also include the identification of the types or specific foods that may be responsible for the allergy. The information gathered in this history can then be used to guide testing decisions and interpretation of results. This systematic approach may help determine whether a history of food allergies and data from laboratory or skin testing are sufficient for diagnosis. If they are not, an oral food challenge (OFC) may be considered to assist in the correct identification of the offending allergens.


Tools for Understanding Allergies


Track allergy symptoms and prepare for a visit with a healthcare provider.

Learn about specific allergens, including common symptoms, management, and relief. 

Are you a healthcare provider? Get comprehensive information on hundreds of whole allergens and allergen components.

Related Content

Want to learn more about allergies? Explore a range of topics.

  1. Pawankar R, Holgate ST, Canonica GW, et al. World Allergy Organization (WAO) White Book on Allergy. 2013. Accessed November 2017. 
  2. Kurowski K, Boxer RW. Food allergies: detection and management. Am Fam Physician. 2008;77:1678-1688.
  3. FARE. Food Allergy Research, Facts and Statistics. Accessed January 2018.
  4. Żukiewicz-Sobczak WA, Wróblewska P, Adamczuk P, Kopczyński P. Causes, symptoms and prevention of food allergy. Postepy Dermatol Alergol. 2013;30(2):113-116.
  5. Sampson HA, Aceves S, Bock SA, James J, Jones S, Lang D, et al. Food allergy: a practice parameter update - 2014. J Allergy Clin Immunol. 2014;134:1016–25. e43.
  6. Flokstra-de Blok BM, et al. Health-related quality of life of food allergic patients: comparison with the general population and other diseases. Allergy. 2010;65:238-24.4.
  7. Le TM, Zijlstra WT, van Opstal EY, et al. Food avoidance in children with adverse food reactions: influence of anxiety and clinical parameters. Pediatr Allergy Immunol. 2013:24(7):650-655.
  8. Kashyap RR, Kashyap RS. Oral Allergy Syndrome: An Update for Stomatologists. J Allergy. 2015;2015:543928.
  9. Davis CM, Gupta RS, Aktas ON et al.  Clinical Management of Seafood Allergy. J of Allergy and Clinical Immunology:In Practice. 2020; 8(1); 37-44.
  10. Clark S, et al. Frequency of US emergency department visits for food-related acute allergic reactions. J Allergy Clin Immunol. 2011; 127(3):682-683.    
  11. Burks AW, Tank M, Sicherer S, et al. ICON: Food allergy. J Allergy Clin Immunol. 2012;129:906-920.