Tree nut allergy: risk factors for development, mitigation of reaction risk and current efforts in desensitization

Abstract

Allergy to tree nuts has grown widespread among patients, specifically in the pediatric population, in recent years. In this review, we evaluate and summarize the literature specific to development and treatment of tree nut allergy. The cause of tree nut allergy, such as most food allergies, is unknown; there are theories regarding maternal dietary factors as well as sensitization related to cross-reactivity to peanut allergens. The gold standard for the diagnosis of tree nut allergy is the double-blind, placebo-controlled, oral food challenge; however, simpler and more cost-effective diagnostic methods, such as the skin prick test and serum-specific IgE are often used as a supplement for diagnosis. Management of tree nut allergy consists of dietary avoidance and using epinephrine to manage serious allergic reactions. Alternative therapeutic methods, such as oral and sublingual immunotherapy and modification of allergenic proteins are being explored to develop safer, more effective and long-lasting management of tree nut allergy. We comment on the current studies involving risk factors for sensitization, diagnosis and management of tree nut allergy.

Keywords:

• oral and sublingual immunotherapy
• peanut allergy
• sensitization
• tree nut allergy

Financial & competing interests disclosure

AW Burks is a grantee of the NIH; grantee and board member of FARE; minority stockholder for Allertein Therapeutics, LLC; minority stockholder and consultant for Mastcell Pharmaceuticals; consultant for Regeneron Pharmaceuticals, ActoGenix, SRA International, GLG Research, Genentech, Sanofi US services; contract researcher for Hycor Biomedical and Allergen Research Corporation. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Tree nut allergy prevalence is increasing with 1.1% of the pediatric population affected in 2008.

• Reported breakdown of tree nut allergy from a voluntary registry: 34% walnut, 20% cashew, 15% almond, 9% pecan, 7% pistachio and <5% allergic to hazelnut, Brazil, pine and macadamia.

• Current guidelines do not offer any specific recommendations about the timing of introduction of the most common food allergens and no longer recommend allergen avoidance in pregnancy.

• Diagnostic value of skin prick testing and serum-specific IgE measurements is variable as loose cutoff levels have been reported but do not always predict clinical allergic reaction.

• Double-blind, placebo-controlled oral food challenge remains the gold standard for diagnosis.

• Allergen-specific immunotherapy (IT) has been explored; specific studies include: single tree nut IT in mouse models and hazelnut sublingual IT in humans.

• Novel IT approaches show promise and could drive management of tree nut allergy in a new direction in the coming years.