TOPLINE:

The prevalence of parent-reported tree nut allergies was nearly 6% in Dutch children aged 1-12 years, with walnut, hazelnut, and cashew emerging as the most common allergens. Fewer than one quarter of children were introduced to tree nuts before 12 months of age, although this early introduction was more common among preschoolers and toddlers than among school-aged children.

METHODOLOGY:

• Researchers conducted an observational cohort study in Netherlands to assess the parent-reported prevalence of tree nut allergy and to evaluate consumption patterns of tree nuts in children aged 1-12 years.
• They included 1867 children, comprising 476 toddlers aged 1-3 years, 862 preschoolers aged 4-6 years, and 529 school-aged children aged 7-12 years.
• Parents completed a digital questionnaire accessed via a flyer distributed through municipal health services, primary schools, daycare centres, and social media, reporting on the presence of a tree nut allergy, history of allergic reactions, comorbidities, family burden of atopic diseases, consumption patterns of tree nuts, and the age at initial introduction to tree nuts.
• Primary endpoints included the parent-reported lifetime prevalence of a tree nut allergy and frequency of consumption of tree nuts.

TAKEAWAY:

• The parent-reported prevalence of tree nut allergy was 5.9%, with walnut (3.8%), hazelnut (3.3%), and cashew (3.2%) being the most frequently reported allergens.
• Parent-reported tree nut allergies were significantly associated with parent-reported peanut allergy (odds ratio [OR], 16.95; 95% CI, 7.04-41.67), atopic dermatitis (OR, 3.68; 95% CI, 2.19-6.17), allergic rhinitis (OR, 3.06; 95% CI, 1.69-5.56), and cow's milk allergy (OR, 2.39; 95% CI, 1.14-5.00).
• Hazelnut was the most frequently consumed tree nut (93.9%), with a median intake of once weekly, whereas almond, cashew, and walnut were typically consumed once monthly.
• Only 24.2% of children were first introduced to tree nuts before 12 months of age, and this proportion varied by age group as it increased from 13.5% for school-aged children to 22.1% for preschoolers and 40.2% for toddlers; early introduction was less common in children with a tree nut allergy than in those without (16.0% vs 24.6%; P = .05), with the difference being significant among school-aged children (2.3% vs 14.5%; P = .019).

IN PRACTICE:

"The results of this study underscore the need for increased focus on prevention strategies and development of guidelines aimed at prevention of tree nut allergies, with careful consideration of regional dietary patterns and sensitization risks," the authors wrote.

"Additionally, in collaboration with local health organizations, educational campaigns should be implemented for parents and healthcare providers, highlighting the importance and safety of tree nut introduction and regular ingestion into their children's diets before the age of 12 months, recognizing risk factors for developing tree nut allergies, and identifying early signs of allergic reactions," they added.

SOURCE:

This study was led by M. Fleuren-Janssen, VieCuri Medical Center in Venlo, Netherlands. It was published online on May 19, 2026, in Pediatric Allergy and Immunology.

LIMITATIONS:

The cross-sectional design limited the ability to establish causal inference. Recruiting participants through social media, primary schools, and childcare centres may have introduced responder bias by overrepresenting digitally active, motivated, highly educated, and socioeconomically advantaged families. Additionally, the study relied on parent-reported data, which may have introduced information bias.

DISCLOSURES:

The study was supported by the Science fund of the VieCuri Medical Center, Call 2023. The authors reported having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.