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Diff: Food Allergies

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Food allergies are abnormal immune responses triggered by specific foods. When individuals with food allergies consume or come into contact with allergenic foods, their immune system identifies certain proteins in the food as harmful and releases chemicals, such as histamine, to defend the body. These chemicals cause a range of symptoms, varying from mild to severe, which can affect different organs and systems in the body.

== Overview ==
Food allergies are common worldwide and can affect individuals of all ages. They are most prevalent in children, with some allergies being outgrown over time. However, certain food allergies, such as those to peanuts, tree nuts, shellfish, and fish, tend to persist into adulthood.
	'''Food allergies''' are immune reactions to food. They happen when the immune system reacts to a food protein as if it were harmful. Reactions can be mild, but some food allergies can cause anaphylaxis, a rapid and potentially life-threatening allergic reaction.

While any food can potentially trigger an allergic reaction, certain foods are more commonly associated with food allergies. These include:
	Food allergy is different from food intolerance. Allergy involves the immune system and can become dangerous quickly. Intolerance more often causes digestive or other symptoms without the same immediate anaphylaxis risk.

* Peanuts
* Tree nuts (e.g., almonds, walnuts, cashews)
* Shellfish (e.g., shrimp, crab, lobster)
* Fish
* Milk
* Eggs
* Soy
* Wheat
* Sesame seeds
	== Common Triggers ==
	Any food can cause an allergy, but common triggers include cow's milk, eggs, peanuts, tree nuts, fish, shellfish, wheat, soya, sesame, celery, mustard and lupin.

It is important for individuals with food allergies to carefully read food labels and be vigilant about avoiding allergenic foods to prevent allergic reactions.
	Children may outgrow some allergies, such as milk or egg allergy, but others, including peanut, tree nut, fish and shellfish allergy, are more likely to persist.

== Symptoms ==	== Symptoms ==
The symptoms of a food allergy can vary in their presentation and severity. They typically manifest within minutes to a few hours after consuming the allergenic food. Common symptoms include:
	Symptoms can appear within minutes, although delayed reactions can also happen. Common symptoms include itching or tingling in the mouth, hives, swelling of the lips, face, tongue or throat, wheezing, shortness of breath, feeling dizzy, nausea, vomiting, abdominal pain and diarrhoea.

* Skin: Itchy skin, hives, rash, swelling (angioedema)
* Digestive System: Nausea, vomiting, abdominal pain, diarrhea
* Respiratory System: Sneezing, runny nose, nasal congestion, coughing, wheezing, shortness of breath
* Cardiovascular System: Rapid heartbeat, drop in blood pressure, dizziness, lightheadedness
* Mouth and Throat: Tingling or itching sensation in the mouth, lips, or throat, swelling of the lips or tongue
* Anaphylaxis: In severe cases, a life-threatening allergic reaction known as anaphylaxis can occur, involving a combination of symptoms from multiple organ systems. Anaphylaxis requires immediate medical attention.
	Signs of a severe reaction include breathing difficulty, throat tightness, swelling affecting the airway, collapse, confusion, pale or clammy skin, and symptoms involving more than one body system. These may indicate anaphylaxis.

It is important for individuals with food allergies to recognize the symptoms of an allergic reaction and seek prompt medical care if severe symptoms or anaphylaxis occur.
	== Anaphylaxis ==
	Anaphylaxis needs immediate action. NHS advice is to use an adrenaline auto-injector if one is available, call 999 for an ambulance, and keep the person lying down unless breathing difficulty means they need to sit up slowly. A second auto-injector may be needed if symptoms do not improve after five minutes.

== Diagnosis ==
Diagnosing a food allergy involves a combination of medical history, physical examination, and specialized tests. Healthcare professionals typically consider the following factors:
	People at risk may be prescribed two adrenaline auto-injectors and referred to an allergy specialist. Family, friends, schools, workplaces and carers may need to know where the injectors are kept and how to use them.

* Medical History: Detailed information about the timing and nature of allergic reactions, including specific foods involved.
* Elimination Diet: Temporary removal of suspected allergenic foods from the diet, followed by reintroduction under medical supervision to observe allergic reactions.
* Skin Prick Test: Small amounts of allergenic proteins are applied to the skin using a pricking device, and the skin's reaction is observed for signs of an allergic response.
* Blood Tests: Blood tests measure the levels of specific antibodies, such as immunoglobulin E (IgE), associated with allergic reactions.
	== Diagnosis ==
	Diagnosis is based on the reaction history and, where appropriate, allergy testing. Tests may include skin prick testing, blood tests for specific IgE antibodies and supervised food challenge testing in specialist settings.

A proper diagnosis is crucial to differentiate food allergies from other conditions and to develop a safe management plan.
	Unsupervised food challenges can be dangerous for people who may have severe allergy. A clear history is important because positive tests can show sensitisation without proving that a food causes symptoms.

== Management ==	== Management ==
The primary treatment for food allergies is strict avoidance of allergenic foods. Individuals with food allergies must be diligent in reading food labels, identifying potential sources of allergens, and avoiding cross-contamination during food preparation.

In cases of accidental exposure or mild allergic reactions, over-the-counter antihistamines may help alleviate symptoms. However, in severe cases or during anaphylactic reactions, immediate medical attention is required. Healthcare professionals may prescribe epinephrine auto-injectors (e.g., EpiPen) for individuals at risk of anaphylaxis, providing emergency treatment in case of severe allergic reactions.
	The main management is avoiding the confirmed allergen while maintaining a nutritionally adequate diet. This usually involves reading labels, understanding precautionary allergen statements, avoiding cross-contamination, and communicating clearly with restaurants, schools and carers.

It is crucial for individuals with food allergies to educate themselves, their families, and caregivers about allergen avoidance, recognizing allergic reactions, and appropriate emergency response measures.
	Treatment depends on the reaction. Mild symptoms may be treated with advice from a health professional, while suspected anaphylaxis requires adrenaline and emergency medical help.

== Cross-Reactivity and Oral Allergy Syndrome ==
Some individuals with food allergies may experience cross-reactivity, where proteins in certain foods resemble proteins in other allergenic foods, leading to allergic reactions. For example, individuals with a pollen allergy may experience oral allergy syndrome, which causes itching or swelling of the mouth, lips, or throat when consuming certain fruits, vegetables, or nuts.
	== Labelling and Everyday Risk ==
	Food labels and catering information are a major part of allergy management. In the UK, packaged food must highlight specified allergens in the ingredients list, and food businesses must provide allergen information for non-prepacked food.

Understanding cross-reactivity patterns and being aware of potential triggers can help individuals with food allergies navigate their dietary choices more effectively.
	People with food allergies often carry written plans, auto-injectors and safe snacks. The practical burden can be significant, especially for children, families and people with multiple allergies.

== See Also ==	== See Also ==
	* [[Food_Intolerances]]
	* [[Coeliac_Disease]]
	* [[Anaphylaxis]]
	* [[Immunology]]

* [[Celiac Disease]] - A chronic autoimmune disorder triggered by gluten ingestion.
* [[Gluten Sensitivity]] - Explore adverse reactions to gluten without involving an autoimmune response.
* [[Food Intolerances]] - Learn about non-immune-mediated adverse reactions to certain foods.
	== References ==
	* [https://www.nhs.uk/conditions/food-allergy/ NHS: Food allergy]
	* [https://www.nhs.uk/conditions/anaphylaxis/ NHS: Anaphylaxis]
	* [https://www.nhsinform.scot/illnesses-and-conditions/nutritional/food-allergy/ NHS inform: Food allergy]
	* [https://www.food.gov.uk/safety-hygiene/food-allergy-and-intolerance Food Standards Agency: Food allergy and intolerance]

	[[Category:Medicine]]
	[[Category:Immunology]]
	[[Category:Food]]