Food Allergy Clinic London
Expert diagnosis and treatment for suspected food allergy in adults, children and infants.
Common food allergens such as milk, eggs, nuts and seafood used in food allergy diagnosis London Allergy and Immunology Centre.
Food allergy can affect the skin, gut, breathing and circulation, and reactions may range from mild itching or hives to severe anaphylaxis. Our allergy specialists provide careful assessment, appropriate testing and personalised management plans to help you identify the true trigger and stay safe.
What is food allergy?
Food allergy is an immune system reaction to a food protein. In some people, even a very small amount of the trigger food can cause symptoms. Reactions may happen rapidly, often within minutes to 2 hours in IgE-mediated food allergy, or may be delayed in non-IgE-mediated conditions. Food allergy is different from food intolerance, which does not involve the immune system in the same way and usually does not cause anaphylaxis.
Common trigger foods include cow’s milk, egg, peanut, tree nuts, wheat, soya, sesame, fish and shellfish, although almost any food can cause allergy. Some children outgrow allergies such as milk or egg, while peanut, tree nut, fish and shellfish allergy are more likely to persist into later childhood or adult life.
Food allergy symptoms
Food allergy symptoms can affect several parts of the body. Skin symptoms may include itching, hives, redness, swelling or worsening eczema. Gastrointestinal symptoms may include abdominal pain, vomiting, diarrhoea or feeding difficulties. Respiratory symptoms can include throat tightness, persistent cough, wheeze, noisy breathing or shortness of breath. More severe reactions can affect the circulation and may lead to dizziness, collapse or anaphylaxis.
Some people notice tingling or itching in the mouth after certain fresh fruit, vegetables or nuts during pollen season. This may represent pollen food allergy syndrome, also known as oral allergy syndrome, which is different from classic severe food allergy, although specialist assessment is still important if symptoms are unclear.
Seek urgent help if there is
- Difficulty breathing or wheezing
- Throat tightness or a hoarse voice
- Persistent vomiting after exposure
- Dizziness, faintness or collapse
- Rapid progression of symptoms affecting more than one part of the body
Food allergy or food intolerance?
This is one of the most common questions in clinic. Food allergy involves the immune system and may cause hives, swelling, vomiting, wheeze or anaphylaxis. Food intolerance is different and more often causes digestive symptoms such as bloating, abdominal discomfort or altered bowel habit without the same immune mechanism. Because the symptoms can overlap, careful specialist assessment is important before foods are removed unnecessarily.
Unsupervised exclusion diets can affect nutrition, quality of life and confidence around eating. A clear diagnosis helps patients avoid the right foods, not simply more foods.
How we diagnose food allergy
Diagnosis begins with a detailed clinical history. Your consultant will ask exactly what food was eaten, how much was taken, how quickly symptoms started, what the symptoms were, whether treatment was required and whether the reaction has happened more than once. Timing matters greatly in food allergy, and the pattern of the reaction often gives more useful information than a test result on its own.
Testing may include skin prick testing and blood tests for specific IgE antibodies. In selected cases, component-resolved diagnostics may help refine risk assessment for foods such as peanut or tree nuts. Where the history and tests do not give a clear answer, a medically supervised oral food challenge may be considered. This is the gold standard for confirming whether a food can be eaten safely in selected cases.
Food allergy treatment
Treatment depends on the type of food allergy, the severity of previous reactions, the patient’s age, the nutritional impact and the risk of future exposure. For confirmed allergy, the mainstay of treatment is careful avoidance of the trigger food together with a clear management plan. This may include label reading, guidance for restaurants, travel preparation and written advice for nursery, school or work.
Patients at risk of more serious reactions may need adrenaline auto-injectors and an emergency action plan. Antihistamines may help with mild symptoms such as itching or hives, but they do not replace adrenaline in anaphylaxis. Where clinically appropriate, specialist services may also discuss desensitisation or oral immunotherapy pathways for selected foods and selected patients.
Avoidance and label reading
We provide practical guidance on identifying the true allergen, checking ingredients, understanding precautionary wording and reducing accidental exposure at home and when eating out.
Emergency planning
Where needed, we advise on adrenaline auto-injectors, symptom recognition and written allergy action plans for school, nursery, family members and carers.
Specialist follow-up
Follow-up may include repeat assessment, advice on whether the allergy is likely to be persistent, and discussion of reintroduction or challenge when appropriate.
Anaphylaxis and emergency care
Food allergy is one of the most important causes of anaphylaxis, which is a severe and potentially life-threatening allergic reaction. Symptoms can develop rapidly and may include swelling of the tongue or throat, difficulty breathing, wheeze, persistent cough, dizziness, collapse, or severe vomiting after eating a trigger food. In some patients, symptoms progress quickly and require urgent emergency treatment.
Patients with a history of significant allergic reactions may need adrenaline auto-injectors and a clear written emergency action plan. We help patients and families understand how to recognise the early signs of anaphylaxis, when to use adrenaline, when to call emergency services, and how to reduce the risk of accidental exposure at home, at school, when travelling, and when eating out.
Specialist assessment is important because not every reaction is the same, and the risk profile varies from one patient to another. A careful review can help determine whether emergency medication is needed and ensure that you have practical, personalised advice for everyday life.
Food allergy in babies and children
Food allergy often begins in infancy or early childhood. It may present with hives, swelling, vomiting, reflux-like symptoms, unsettled feeding, eczema flares, loose stools or poor tolerance of certain foods. Cow’s milk and egg are among the most common triggers in younger children, while peanut, tree nuts, sesame and other allergens may also be involved.
Early, accurate diagnosis is important so that families avoid unnecessary diets and children continue to receive safe, nutritionally appropriate feeding. We provide practical advice for weaning, nursery and school planning, packed lunches, birthday parties and travel.
Common food allergies we assess
Egg allergy
Peanut allergy
Tree nut allergy
Sesame allergy
Wheat allergy
Soya allergy
Fish allergy
Shellfish allergy
Frequently asked questions about food allergy
Can a blood test alone diagnose food allergy?
No. Blood tests and skin prick tests can support the diagnosis, but they must be interpreted alongside the history. A positive test without convincing symptoms does not always mean true clinical allergy.
What is an oral food challenge?
An oral food challenge is a carefully supervised medical test in which a food is introduced in measured amounts to assess whether it can be eaten safely. It is usually reserved for selected cases after specialist review.
Can children outgrow food allergy?
Some children outgrow allergies such as milk or egg, but others persist for longer. Peanut, tree nut, fish and shellfish allergy are often more persistent, although this varies from person to person.
Do I need adrenaline auto-injectors?
This depends on your history, the type of reaction, the trigger food and other risk factors such as asthma. A specialist assessment is important to decide whether they are needed.
Should I avoid foods before I am properly assessed?
If you have had a convincing allergic reaction, strict avoidance of the suspected trigger is sensible until specialist review. However, broad unnecessary food restriction should be avoided wherever possible because it may complicate diagnosis and nutrition.
Book a food allergy assessment
If you or your child have reacted to a food, our clinic can help with specialist diagnosis, targeted testing and a personalised management plan. We aim to give clear answers, reduce uncertainty and support safer day-to-day living.
A specialist review can help clarify whether symptoms fit true food allergy, whether emergency medication is needed, and whether future reintroduction or challenge may be appropriate.