--- title: "Food allergy: Symptoms, Causes & Treatment | HealthAnswers" description: "Food allergy — common triggers, symptoms from mild to anaphylaxis, NHS diagnosis, management including avoidance and adrenaline auto-injectors." url: https://healthanswers.co.uk/conditions/food-allergy/ robots: noindex --- # Food allergy: Symptoms, Causes & Treatment | HealthAnswers Health A–Z Food allergy — common triggers, symptoms from mild to anaphylaxis, NHS diagnosis, management including avoidance and adrenaline auto-injectors. Written by HealthAnswers editorial team Medically reviewed by [HealthAnswers UK doctor review panel](https://healthanswers.co.uk/our-doctors/) Reviewed 3 July 2026 ## Quick answer What is food allergy? A food allergy is when the immune system reacts to a specific food protein, causing symptoms ranging from mild itching and hives to life-threatening anaphylaxis. Common triggers in the UK include peanuts, tree nuts, milk, eggs, wheat, fish, shellfish, sesame, and soy. Diagnosis involves history, skin prick tests, and blood tests. Management is strict avoidance of the trigger food, carrying adrenaline auto-injectors if prescribed, and an allergy action plan. ## Who is this page for? This page is for people in the UK who want a plain-English overview of Food allergy, including when to seek help and what NHS care usually involves. It explains general information, not what is wrong with you personally. ## Who should skip this page? Skip this page if you need a diagnosis, a prescription, or emergency care. It cannot replace a GP, pharmacist, NHS 111 or 999. If you are in immediate danger, call 999; for urgent advice that is not life-threatening, call 111 in England, Scotland or Wales, or use your GP out-of-hours service in Northern Ireland. On this page 7 sections ## Key facts about food allergy - Food allergy involves an immune reaction to specific food proteins — different from food intolerance which does not involve IgE antibodies. - Common allergens in the UK include peanuts, tree nuts, milk, eggs, fish, shellfish, wheat, sesame, and soy. - Symptoms range from hives and vomiting to anaphylaxis — swelling of throat, breathing difficulty, collapse. - Peanut and tree nut allergies often persist for life — milk and egg allergy commonly resolve in childhood. - People at risk of anaphylaxis should carry two adrenaline auto-injectors and have an allergy action plan. ## Food allergy — when eating triggers an immune reaction A **food allergy** happens when the immune system mistakenly treats a harmless **food protein** as a threat, triggering a reaction that can range from **mild itching** to **life-threatening anaphylaxis**. Food allergy is **different from food intolerance** — intolerance does not involve the same immune pathway and is not immediately dangerous. Getting the distinction right matters for **safety and treatment**. ## Common food allergens in the UK UK food law requires labelling of **14 major allergens**: - Peanuts and tree nuts (almonds, walnuts, cashews, etc.) - Milk and eggs - Fish and shellfish (crustaceans and molluscs) - Wheat (gluten-containing cereals) - Soy , sesame , mustard , celery , lupin - Sulphur dioxide (preservative in dried fruit and wine) **Peanut and tree nut allergies** are among the most common causes of **severe reactions** and often **persist for life**. ## Symptoms Reactions usually start within **minutes to 2 hours** of eating. **Mild to moderate:** - Itching in mouth or throat - Hives (urticaria) — raised itchy welts - Swelling of lips, face, or eyes - Vomiting, stomach cramps, diarrhoea - Runny nose or sneezing **Anaphylaxis — call 999:** - Difficulty breathing or wheezing - Throat or tongue swelling - Feeling faint or collapsing - Rapid heartbeat - Widespread hives with systemic symptoms ## Diagnosis - Detailed history — what was eaten, how much, how quickly symptoms appeared, and what happened on re-exposure - Skin prick testing — small amounts of allergen on the skin - Specific IgE blood tests — measure allergic antibodies - Oral food challenge — gold standard in specialist settings Avoid **unvalidated tests** sold online — IgG food panels are not recommended by NICE for diagnosing allergy. ## Management **Strict avoidance** of the confirmed allergen — read every label, ask in restaurants, inform schools and workplaces. **Adrenaline auto-injectors** — prescribed for people at risk of anaphylaxis. Carry **two devices** always. Train family and carers to use them. **Allergy action plan** — written plan from your allergy team covering symptoms and when to use adrenaline. **Antihistamines** — for mild reactions; do not rely on them for anaphylaxis. **Allergen immunotherapy** — peanut oral immunotherapy available in specialist NHS centres for selected patients. ## Food allergy in children **Milk, egg, wheat, and soy allergies** commonly appear in infancy — many children **outgrow** them by school age. **Peanut, tree nut, fish, and shellfish allergies** more often persist. **Early introduction** of peanut and egg from around **6 months** — in babies who are developmentally ready — may **reduce allergy risk**, including in infants with eczema. Discuss with your health visitor. ## Food allergy vs coeliac disease **Coeliac disease** is an autoimmune reaction to **gluten** — not a classic IgE food allergy. It causes gut damage over time. See [coeliac disease](https://healthanswers.co.uk/conditions/coeliac-disease/) for gluten-related illness. See [hives](https://healthanswers.co.uk/conditions/hives/) for allergic skin reactions. ## ! When to see a GP about food allergy Call **999** and use an adrenaline auto-injector if someone develops difficulty breathing, throat or tongue swelling, widespread hives with feeling faint, or collapse after eating — possible anaphylaxis. See a GP if you suspect a food allergy — reproducible symptoms within minutes to 2 hours of eating a specific food. Do not self-diagnose — a GP refers to allergy clinic for testing. Seek urgent help for any allergic reaction that does not respond to antihistamines or is worsening. ## Common questions about food allergy What is the difference between food allergy and food intolerance? Food allergy is an immune system reaction — usually involving IgE antibodies — that can cause rapid, sometimes severe symptoms including anaphylaxis. Food intolerance — such as lactose intolerance — does not involve the immune system in the same way, causes slower symptoms like bloating and diarrhoea, and is not life-threatening. What are the symptoms of a food allergy? Symptoms usually appear within minutes to 2 hours of eating. Mild to moderate — itching, hives, lip or face swelling, vomiting, diarrhoea, runny nose. Severe (anaphylaxis) — difficulty breathing, throat tightness, wheeze, dizziness, collapse, rapid heartbeat. Anaphylaxis is a medical emergency. Which foods most commonly cause allergy in the UK? The 14 major allergens regulated in UK food labelling are celery, gluten-containing cereals, crustaceans, eggs, fish, lupin, milk, molluscs, mustard, nuts, peanuts, sesame, soy, and sulphur dioxide. Peanuts and tree nuts cause the most severe reactions in adults and children. How is food allergy diagnosed? A detailed history of reactions is essential. Allergy specialists use skin prick tests and specific IgE blood tests to identify triggers. Oral food challenges — eating the food under medical supervision — confirm or rule out allergy in some cases. Do not rely on unvalidated commercial tests. Can food allergies be cured? There is no cure yet. Strict avoidance of the allergen is the mainstay. Some children outgrow milk, egg, wheat, and soy allergies. Peanut and tree nut allergies more often persist. Oral immunotherapy for peanut allergy is available in specialist centres for selected patients. What is an adrenaline auto-injector? Devices such as EpiPen, Jext, or Emerade deliver a fixed dose of adrenaline (epinephrine) to treat anaphylaxis. People with a history of anaphylaxis or significant allergy should carry two devices at all times. Use at the first sign of anaphylaxis, call 999, and lie flat with legs raised unless vomiting. How do I manage food allergy day to day? Read food labels carefully — allergens must be highlighted. Inform restaurants and schools. Avoid cross-contamination when cooking. Wear medical alert identification. Follow your allergy action plan. Attend regular allergy clinic follow-up — especially for children. Can breastfeeding prevent food allergy in babies? Exclusively breastfeeding for around 6 months may reduce eczema risk. Introducing allergenic foods — peanut, egg — from around 6 months in developmentally ready infants may reduce allergy risk, including in babies with eczema. Discuss timing with your health visitor or GP. ## Sources - [NHS — Food allergy](https://www.nhs.uk/conditions/food-allergy/) - [NICE — Food allergy](https://www.nice.org.uk/guidance/cg116) - [NHS — Anaphylaxis](https://www.nhs.uk/conditions/anaphylaxis/)