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A food allergy is an abnormal immune response to food. The signs and symptoms may range from mild to severe. They may include itchiness, swelling of the tongue, vomiting, diarrhea, hives, trouble breathing, or low blood pressure. This typically occurs within minutes to several hours of exposure. When the symptoms are severe it is known as anaphylaxis. Food intolerance and food poisoning are separate conditions.〔 Common foods involved include cow's milk, peanuts, eggs, shellfish, tree nuts, wheat, rice, and fruit.〔〔 Which allergies are most common depends on the country.〔 Risk factors include a family history of allergies, vitamin D deficiency, obesity, and high levels of cleanliness.〔〔 Allergies occur when immunoglobulin E (IgE), part of the body's immune system, binds to food molecules.〔 It is usually a protein in the food that is the problem.〔 This triggers the release of inflammatory chemicals such as histamine.〔 Diagnosis is usually based on a medical history, elimination diet, skin prick test, blood tests for food-specific IgE antibodies, or oral food challenge.〔〔 Early exposure to potential allergens may be protective. Management primarily involves avoiding the food in question and having a plan if exposure occurs.〔 This plan may include giving adrenaline (epinephrine) and wearing medical alert jewelry.〔 The benefits of allergen immunotherapy for food allergies is unclear and thus not recommended as of 2015.〔(【引用サイトリンク】url=http://www.niaid.nih.gov/topics/allergicdiseases/Pages/allergen-immunotherapy.aspx )〕 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.〔 In the developed world about 4% to 8% of people have at least one food allergy. They are more common in children than adults and appear to be increasing in frequency. Male children appear to be more commonly affected than females.〔 Some allergies more commonly develop early in life while others typically develop in later life.〔 In developed countries, a large proportion of people believe they have food allergies when they actually do not have them. == Signs and symptoms == Food allergies have a fast onset (from seconds to one hour) and may include: *Rash *Hives〔 *Itching of mouth, lips, tongue, throat, eyes, skin, or other areas〔 *Swelling (angioedema) of lips, tongue, eyelids, or the whole face〔 *Difficulty swallowing〔 *Runny or congested nose〔 *Hoarse voice〔 *Wheezing and/or shortness of breath〔 *Nausea〔 *Vomiting〔 *Abdominal pain and/or stomach cramps〔 *Lightheadedness〔 *Fainting〔 Symptoms of allergies vary from person to person. The amount of food needed to trigger a reaction also varies from person to person. Serious danger regarding allergies can begin when the respiratory tract or blood circulation is affected. The latter can be indicated through wheezing and cyanosis. Poor blood circulation leads to a weak pulse, pale skin, and fainting.〔van Ree 1〕 A severe case of an allergic reaction, caused by symptoms affecting the respiratory tract and blood circulation, is called anaphylaxis. When symptoms are related to a drop in blood pressure, the person is said to be in anaphylactic shock. Anaphylaxis occurs when IgE Antibodies are involved, and areas of the body that are not in direct contact with the food become affected and show symptoms. This occurs because no nutrients are circulated throughout the body, causing the widening of blood vessels. This vasodilation causes blood pressure to decrease, which leads to the loss of consciousness. Those with asthma or an allergy to peanuts, tree nuts, or seafood are at greater risk for anaphylaxis.〔(Food Allergies ). Food Allergy Initiative. 2009. Accessed 27 Mar 2010.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Food allergy」の詳細全文を読む スポンサード リンク
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