Peanut Allergy Diagnosis and Treatment

Expert care for allergic reactions affecting skin, breathing and overall wellbeing

Peanut allergy is one of the most common food allergies in children and one of the least likely to be outgrown, affecting approximately 2% of children in the UK. Reactions range from mild skin symptoms to life-threatening anaphylaxis. We diagnose, treat and prevent peanut allergy under the leadership of Professor Gideon Lack, whose LEAP study showed that early introduction of peanut reduces allergy risk by 81% in high-risk infants, and whose LEAP-Trio follow-up showed that protection lasts into adolescence.

Precise diagnosis using skin, blood and supervised challenge testing
Oral immunotherapy for suitable children, retraining the immune system rather than only avoiding peanut
Prevention protocols built on the LEAP, EAT and LEAP-Trio studies our team ran
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What is peanut allergy?

Peanut allergy occurs when your immune system mistakenly identifies peanut proteins as harmful and triggers an allergic reaction. Despite being classified as legumes rather than true nuts, peanuts are one of the most common food allergens, affecting approximately 2% of children in the UK (around 1 in 50).

Unlike some food allergies that children outgrow, peanut allergy often persists into adulthood, with only about 20% of children developing tolerance over time. Reactions can range from mild skin symptoms to severe, life-threatening anaphylaxis, making accurate diagnosis and management essential.

Peanut allergy has become significantly more common in recent decades. That rise is what prompted Professor Lack's research into prevention, and it is why our clinic treats peanut allergy not as a fixed diagnosis but as a condition to be prevented where possible, treated where suitable, and managed with precision everywhere else.

Symptoms of peanut allergy

Allergic reactions to peanuts typically occur within minutes to two hours after exposure and can affect multiple body systems. For many patients with peanut allergy, even trace amounts can trigger significant reactions. Cross-contamination in food preparation is a significant concern, as peanuts are common ingredients in many foods and may be present even when not listed as a main ingredient.
Mild to moderate reactions
  • Skin reactions (hives, redness, itching)
  • Swelling of lips, face or eyes
  • Tingling or itching in the mouth and throat
  • Nausea, vomiting or abdominal pain
  • Runny nose or sneezing
Severe reactions
  • Difficulty breathing or wheezing
  • Swelling of the tongue
  • Tightness in the throat
  • Hoarse voice or trouble swallowing
  • Dizziness, confusion or collapse
  • Pale and floppy (in young children)

How we diagnose peanut allergy

Our approach to diagnosing peanut allergy combines detailed clinical assessment with the full range of specialist testing. Testing distinguishes true peanut allergy from sensitisation (having antibodies but no clinical reactions), so you receive clear guidance without unnecessary dietary restrictions.
Detailed assessment
Detailed medical history focusing on reaction patterns
Skin prick testing to measure sensitivity to peanut proteins
Blood tests to measure peanut-specific IgE antibodies
Component resolved diagnostics to identify which specific peanut proteins your child reacts to, which sharpens the risk assessment
Oral food challenges in a controlled, safe environment when appropriate

Treating peanut allergy

Avoidance is no longer the only option. Oral immunotherapy trains the immune system to tolerate peanut through carefully supervised, gradually increasing doses. For suitable children, it can raise the threshold that triggers a reaction from a trace to a meaningful amount, reducing the risk attached to accidental exposure; in very young children, it can induce full tolerance. Our team assesses every child's suitability for oral immunotherapy as part of their diagnosis, and delivers the programme in clinic with specialist supervision at every step.
For around 20% of children, peanut allergy resolves on its own; supervised food challenges are how we confirm it, so a family can stop avoiding peanut with confidence rather than guessing.

Managing peanut allergy

Drawing on our clinical experience, we develop tailored management plans for each patient with peanut allergy. Our approach is informed by Professor Lack's research, including the LEAP (Learning Early About Peanut allergy) study that changed allergy prevention worldwide.
Personalised approach
  • Specific avoidance strategies while maintaining nutritional balance
  • Education on reading food labels and identifying hidden peanut ingredients
  • Emergency action plans for managing accidental exposures
  • Guidance for managing peanut allergy in schools, workplaces, and restaurants
  • Support for families in creating safe environments
Prevention and treatment
  • Early introduction protocols for infants at risk of developing peanut allergy
  • Assessment of potential cross-reactivity with tree nuts
  • Regular monitoring to track changes in allergy patterns
  • Oral immunotherapy for suitable candidates

Why choose LACK for peanut allergy care

Peanut allergy is the condition this clinic is known for worldwide:
Led by Professor Gideon Lack, whose LEAP study transformed global approaches to peanut allergy prevention and who was named in the TIME100 Health list in 2026
Evidence from our own studies: LEAP, EAT, LEAP-On and LEAP-Trio
The full range of diagnostic testing, including component resolved diagnostics
Specialised protocols for infants and young children at risk
Personalised emergency action plans and family support
Oral immunotherapy delivered under specialist supervision
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Eczema
“As far as our family is concerned, Professor Lack is a miracle worker. We trust his advice implicitly and are very lucky to have him as our daughter’s specialist.”
Eczema
28th Sept 2024
Eczema
verified patient

Pioneering research, personalised care

Our approach combines research into allergy prevention with deeply personalised care. Professor Lack's LEAP study was the first to show that early introduction of peanut could prevent allergy development in high-risk infants: regular peanut consumption in infancy led to an 81% reduction in peanut allergy compared to avoidance, and global guidelines changed as a result. Prevention that lasts is now the standard we work to, for patients with existing allergy and for the younger siblings we can still protect.
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Frequently asked questions

How is peanut allergy tested?

We use three methods, usually in combination. A skin prick test gives a measurable result within 20 minutes of the appointment. A blood test measures peanut-specific IgE antibodies, and component testing identifies which individual peanut proteins are involved, which helps predict whether reactions are likely to be significant. Where results are borderline, a supervised oral food challenge gives a definitive answer. Testing is safe from infancy.

Can peanut allergy be treated or cured?

For most children, oral immunotherapy retrains the immune system rather than removing the allergy: carefully supervised doses gradually raise the amount of peanut your child tolerates, so a trace exposure is far less likely to cause a reaction, and regular consumption maintains that protection. In very young children, treatment can go further and induce full tolerance, which is one reason early assessment matters. Our specialists will assess what is realistic for your child. Around 20% of children also outgrow peanut allergy naturally, which we confirm through supervised food challenges.

If my child is allergic to peanuts, should they also avoid tree nuts?

Having a peanut allergy doesn't automatically mean your child is allergic to tree nuts (like almonds, cashews, and walnuts), as peanuts are actually legumes, not nuts. However, about 30-40% of children with peanut allergy do react to one or more tree nuts as well. Testing each nut individually determines your child's specific allergy profile, allowing them to safely include non-allergenic nuts in their diet when appropriate rather than unnecessarily restricting nutritious foods.

Can children outgrow peanut allergy?

While peanut allergy is often lifelong, approximately 20% of children do outgrow it. Regular assessment by our specialists can track changes in your child's allergy and determine if they're developing tolerance. This may include carefully supervised food challenges when appropriate. Even when complete resolution doesn't occur, some children may experience a decrease in sensitivity over time.

Children most likely to outgrow peanut allergy typically have:

  • Lower levels of peanut-specific IgE antibodies
  • Milder initial reactions
  • Fewer other allergic conditions
How do I manage a child's peanut allergy at school?

Managing peanut allergy in school settings requires collaboration between parents, school staff, and healthcare providers.

We help families develop practical school management plans that include:

  • Age-appropriate education for the child about their allergy
  • Clear emergency action plans for school staff
  • Training on recognition of symptoms and use of emergency medications
  • Strategies for navigating school meals, class parties, and field trips
Is it safe to eat foods labelled "may contain traces of peanuts"?

For people with peanut allergy, cautionary labelling such as "may contain traces" or "manufactured in a facility that processes peanuts" indicates potential cross-contamination risk. The safety of consuming these products depends on your individual sensitivity level. Our specialists can help assess your risk based on your allergy history and test results, and provide personalised guidance on how to interpret these labels. For highly sensitive individuals, we typically recommend avoiding products with precautionary peanut labelling.

What is Professor Lack's approach to preventing peanut allergy?

Professor Lack's groundbreaking LEAP (Learning Early About Peanut Allergy) study transformed our understanding of food allergy prevention. The research demonstrated that regular consumption of peanut in high-risk infants from 4-11 months of age reduced their risk of developing peanut allergy by 81% compared to peanut avoidance. Based on this research, we recommend:

  • Early introduction of peanut for infants, particularly those at high risk
  • Regular consumption to maintain tolerance
  • Careful introduction protocols tailored to each child's risk profile
  • Continued consumption even after tolerance is established

This evidence-based approach has been adopted in clinical guidelines worldwide and forms the foundation of our prevention strategies at LACK Clinic. The LEAP-Trio follow-up, published in 2024, confirmed the protection lasts: a 71% reduction in peanut allergy persisting into adolescence.

Ready to manage peanut allergy with confidence?

Our specialist team can help you navigate life with peanut allergy through accurate diagnosis, personalised management plans, and ongoing support.
Speak to our Team
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Allergy Centre of Excellence (ACE)
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London W1G 9AB
The Portland Hospital 

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