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Chapters
0:00 Introduction
1:31 Causes of Food Allergy
2:54 Symptoms of Food Allergy
3:27 Diagnosis of Food Allergy
4:18 Treatment of Food Allergy
A food allergy is an abnormal immune response to food.[1] The symptoms of the allergic reaction may range from mild to severe.[1] They may include itchiness, swelling of the tongue, vomiting, diarrhea, hives, trouble breathing, or low blood pressure.[1] This typically occurs within minutes to several hours of exposure.[1] When the symptoms are severe, it is known as anaphylaxis.[1] A food intolerance and food poisoning are separate conditions, not due to an immune response.[1][4]
Common foods involved include cow's milk, peanuts, eggs, shellfish, fish, tree nuts, soy, wheat, rice, and fruit.[1][2][5] The common allergies vary depending on the country.[1] Risk factors include a family history of allergies, vitamin D deficiency, obesity, and high levels of cleanliness.[1][2] Allergies occur when immunoglobulin E (IgE), part of the body's immune system, binds to food molecules.[1] A protein in the food is usually the problem.[2] This triggers the release of inflammatory chemicals such as histamine.[1] Diagnosis is usually based on a medical history, elimination diet, skin prick test, blood tests for food-specific IgE antibodies, or oral food challenge.[1][2]
Early exposure to potential allergens may be protective.[2][3] Management primarily involves avoiding the food in question and having a plan if exposure occurs.[2] This plan may include giving adrenaline (epinephrine) and wearing medical alert jewelry.[1] The benefits of allergen immunotherapy for food allergies is unclear, thus is not recommended as of 2015.[6] Some types of food allergies among children resolve with age, including that to milk, eggs, and soy; while others such as to nuts and shellfish typically do not.[2]
In the developed world, about 4% to 8% of people have at least one food allergy.[1][2] They are more common in children than adults and appear to be increasing in frequency.[2] Male children appear to be more commonly affected than females.[2] Some allergies more commonly develop early in life, while others typically develop in later life.[1] In developed countries, a large proportion of people believe they have food allergies when they actually do not have them.[7][8][9] The declaration of the presence of trace amounts of allergens in foods is mandatory only in Brazil.[10][11][12]