Walnut and Pecan Nut OIT
Walnut is a commonly eaten tree nut and a common allergen.
There is a significant risk of co-allergy with pecans due to their nearly identical protein structures.
In addition to baked goods, walnuts are often present in pesto (especially in more traditional Italian varieties), dressings, meat substitutes, and flavoured coffees, making them difficult to avoid.
Walnut Allergy is rarely outgrown and typically requires lifelong vigilance and the constant availability of an epinephrine or nasal-adrenaline device to treat more severe allergic reactions.
Oral Immunotherapy (OIT) is an emerging treatment in which patients ingest micro-doses of walnut protein under medical supervision to build tolerance and help prevent accidental reactions.
Diagnosis:
Diagnosing walnut allergy involves a thorough clinical history, skin prick testing, and assessment of specific IgE levels to whole extracts and Walnut and Pecan IgE components.
If all this information results in an uncertain diagnosis, then oral food challenges in a safe and supervised setting, such as our ACE centre, will be recommended.
Which nuts does walnut often cross-react with?
Walnut and pecan are closely related, leading to significant cross-reactivity due to shared allergenic proteins.
All patients allergic to pecans are also allergic to walnuts; however, not all walnut-allergic individuals will react to pecans.
Hazelnut is considered a more distant relative.
Can a walnut allergy cause a severe reaction?
Yes, walnut and pecan allergies can cause severe and potentially life-threatening reactions.
These allergies are rarely outgrown, necessitating strict avoidance of the allergens.
Emergency preparedness is crucial.
We recommend individualised avoidance strategies rather than eliminating all tree nuts, as many patients can tolerate specific tree nuts despite co-sensitisation. We will guide you through this shared decision-making process.
Tell us about OIT to Walnut and Pecan:
Oral immunotherapy (OIT) has been the most extensively studied approach and shows promise in preventing allergic reactions due to accidental exposure.
Oral immunotherapy (OIT) appears effective in preventing allergic reactions to accidental exposure.
We offer OIT in our Allergy Centre of Excellence OIT Service.
At the end of a year of walnut maintenance dosing, we include a pecan challenge; three pecan nuts are nearly always tolerated after walnut therapy, but the response to hazelnut (a more distant ‘relative’) is far less certain at around 50%.
What are the other treatment options for a nut allergy?
Omalizumab monotherapy is currently the only FDA-approved alternative for reducing allergic reactions to accidental exposure in patients with multiple food allergies
Omalizumab monotherapy is the only approved alternative for reducing allergic reactions to accidental exposure in multi-food allergic patients.
We offer Omalizumab and its Biosimilar in our London Allergy Consultant clinic.
Frequently Asked Questions
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Diagnosis relies on a detailed clinical history, skin prick testing, specific IgE to Walnut and Pecan whole extracts and Walnut and Pecan IgE components.
We also make use of oral food challenges if needed to resolve diagnostic uncertainty.
The EAACI guidelines emphasise that CRD (e.g., Jug r 1, Jug r 4 for walnut) and basophil activation testing (BAT) improve diagnostic accuracy and can reduce unnecessary oral food challenges.
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There are increasing options:
Avoidance, with a bespoke emergency plan
OIT, in our ACE service
SLIT, in our ACE service (not yet available)
Anti-IgE therapy is available in our practice.
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Walnut and Pecan IgE-mediated allergies are seldom outgrown.
Specific IgE levels will usually increase with age, as will reactive symptom severity.
The threshold needed to react may decrease with age, hence older children are at greater risk of more severe allergic resactions
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At the Allergy Centre of Excellence we pride ourselves in:
The UK’s Largest Provider of OIT. We have wonderful facilities and an efficient, empathetic and knowledgeable admin team.
Elite Clinical Team: Led by renowned allergy specialist Professors, Nurses, Dietitians, Psychologists and on-site PICU doctors.
24/7 Peace of Mind: Round-the-clock emergency support for all patients.
Trusted Care: Highly rated by patients and families for clinical outcomes and support.
Strict Governance and oversight.
Worried About Allergies? Let’s Help You Get Answers
If your child is showing signs of a food, pollen, or skin allergy, early diagnosis is key. At London Allergy Consultants, our expert team provides trusted, evidence-based care tailored to your child’s needs. From testing to treatment plans, we guide you every step of the way.
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London Allergy Consultants is a leading UK centre for diagnosing and treating food and airborne allergies in children and young people.
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Walnut allergies are a leading cause of nut-induced allergic reactions, including anaphylaxis.
There is a high risk of "co-allergy" with pecans due to nearly identical protein structures, so allergy (or tolerance) to one usually implies an allergy (or tolerance) to the other, akin to being close ‘first cousins’.
Wlanut and Pecan allergies are rarely outgrown and typically require lifelong vigilance and, in the absence of OIT, the constant presence of an epinephrine auto-injector or Neffy device.
Oral Immunotherapy (OIT) is an emerging treatment option for Walnut and Pecan Allergy. We offer this service.