Peanut and tree nut allergies are among the most common and clinically significant food allergies in children and are a leading cause of severe allergic reactions and anaphylaxis 1. Early and accurate diagnosis is essential to prevent life-threatening reactions and to avoid unnecessary dietary restrictions, which may have a substantial impact on quality of life. In routine clinical practice, skin prick testing (SPT) and allergen-specific IgE (sIgE) measurements are commonly used to assess allergic sensitisation, as recommended in international guidelines 1. However, neither test reliably distinguishes clinically allergic children from tolerant ones, and diagnostic performance varies by allergen 2, 3. Increasing evidence suggests that combining diagnostic modalities, including component-resolved diagnostics, may improve clinical decision-making 4, 5. Nevertheless, the extent to which SPT and sIgE provide overlapping or complementary information across different nuts remains unclear. This study evaluated the concordance between SPT and sIgE to whole nut extracts in children with suspected peanut or tree nut allergy. The study was conducted within the Tampere ALL NUTS cohort, an ongoing single-centre study at Tampere University Hospital, Finland. The cohort consists of children referred to a paediatric allergist due to suspected severe peanut and/or tree nut allergy. Although the Tampere ALL NUTS cohort is an ongoing prospective study with a predefined and systematic diagnostic protocol, the present analysis was based on a retrospective review of clinical data collected through this protocol. The cohort is specifically designed to investigate children with suspected severe nut allergy and to provide a comprehensive diagnostic evaluation for this high-risk group. Children aged 3–15 years were included based on a history of anaphylaxis or other severe reaction caused by peanut or tree nuts and/or a positive molecular IgE result associated with a risk of clinical allergy. Tree nut allergies included in the study were cashew, macadamia, Brazil nut, pecan, pistachio, walnut, almond and hazelnut. All patients who met the inclusion criteria were invited to meet a paediatric allergist at the Allergy Centre of Tampere University Hospital between 2021 and 2024. Written informed consent was obtained prior to enrolment. The study protocol was reviewed and approved by the Institutional Ethics Committee of the Pirkanmaa Hospital District (registration number ETL R21024). Nut-specific SPTs were performed using standardised extracts, with a wheal diameter of ≥ 3 mm considered positive. Corresponding sIgE concentrations to whole nut extracts were measured using the ImmunoCAP method, with values ≥ 0.35 kU/L defined as positive. Ninety-four children with complete paired SPT and sIgE results were included in the analysis. Agreement between binary SPT and sIgE outcomes was assessed using Cohen's kappa and correlations between SPT wheal size and sIgE concentration were assessed using Spearman's rank correlation. The strength of agreement between SPT and sIgE varied substantially by nut. Categorical agreement was strongest for cashew and pecan, moderate for peanut, pistachio and walnut, and only fair for almond, Brazil nut and hazelnut. Macadamia showed minimal concordance between the two tests. Correlations between SPT wheal size and sIgE concentration were generally modest and statistically significant only for peanut, almond, walnut and pecan. (Table 1). Overall, the concordance between SPT and sIgE to whole nut extracts varied markedly between different nuts. High categorical agreement did not consistently translate into strong quantitative correlations, underscoring that SPT and sIgE reflect different biological aspects of allergic sensitisation and should not be considered interchangeable. This inconsistency suggests that while the two tests often show concordant positive or negative results, the degree of sensitisation measured by each method may not align. The weak concordance observed for nuts such as hazelnut, Brazil nut and macadamia suggests limited diagnostic utility of whole-extract testing for these allergens. Although severe macadamia allergy is considered rare, our findings raise questions about the clinical utility of conventional SPT and sIgE for this allergen. Previous studies have demonstrated superior diagnostic accuracy of component-resolved diagnostics, such as Cor a 14 for hazelnut and Ana o 1–3 for cashew, in identifying clinically relevant allergy in children 4, 5. Combining SPT and sIgE with component-resolved diagnostics or oral food challenges could help minimise false-negative or false-positive results. Some limitations should be acknowledged. The single-centre design and enrichment for children with suspected severe nut allergy may limit generalisability to milder allergy phenotypes and other populations. This study also has several strengths. The well-characterised high-risk paediatric cohort increases the clinical relevance of the findings for high-risk patients commonly encountered in specialist care. The inclusion of peanut and multiple tree nuts enabled the identification of allergen-specific differences in diagnostic concordance. These findings suggest that neither SPT nor sIgE alone can reliably provide a complete diagnostic picture in paediatric nut allergy. While the two tests broadly agree in identifying sensitised versus non-sensitised patients, they reflect different aspects of the allergic response, and their concordance varies markedly between individual nuts. Agreement was strongest for cashew and pecan, whereas macadamia showed minimal concordance between the two tests. From a clinical perspective, this underscores the need for allergen-specific interpretation of diagnostic results. High concordance between SPT and sIgE for certain nuts may provide reassurance in clinical decision-making, whereas discordant or weakly associated results should prompt cautious interpretation. For nuts with limited concordance, reliance on whole-extract testing alone may increase the risk of misclassification, and component-resolved diagnostics and, when appropriate, oral food challenges remain essential tools to guide individualised management. Pauliina Uusi-Kokko: writing – original draft, methodology, visualization, writing – review and editing, formal analysis, data curation, resources, investigation. Lauri Lehtimäki: methodology, validation, writing – review and editing. Jussi Karjalainen: methodology, validation, writing – review and editing. Iida Ojaniemi: investigation, resources, writing – review and editing. Heini Huhtala: validation, writing – review and editing. Marjukka Härkönen: writing – review and editing. Jennifer L. P. Protudjer: writing – review and editing. Juho E. Kivistö: conceptualization, methodology, validation, investigation, resources, writing – review and editing, supervision, project administration, funding acquisition. We want to thank nurses Auli Silvonen, Milja Tarvainen and Sanna Koskinen from the Allergy Centre in Tampere University Hospital for the recruiting process. This study was funded by the Tampere Tuberculosis Foundation, the Competitive State Research Financing of the Expert Responsibility area of Tampere University Hospital, Lastentautien tutkimussäätiö, Allergiatutkimussäätiö and The Research Foundation of the Pulmonary Diseases. This work was supported by Tampereen Tuberkuloosisäätiö. The Competitive State Research Financing of the Expert Responsibility area of Tampere University Hospital. Allergiatutkimussäätiö Lastentautien Tutkimussäätiö. The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.
Uusi‐Kokko et al. (Sat,) studied this question.