Key factors in the diagnosis of sesame allergy in children

Background: Sesame allergy (SA) is diagnostically challenging in childhood, and data on its natural course and clinical nonreactivity development are limited. Although oral food challenge (OFC) remains the diagnostic criterion standard, the value of skin-prick tests (SPT) and sesame specific immunoglobulin E (sIgE) in diagnosis and clinical nonreactivity prediction is unclear. Objective: The objective was to assess the diagnostic accuracy of tahini SPT and sesame sIgE, and to determine the frequency of clinical nonreactivity and identify clinical and laboratory factors associated with clinical nonreactivity development in children undergoing tahini-based OFC. Methods: In this retrospective diagnostic accuracy study, 49 children with suspected SA were included. All participants underwent open tahini-based OFC. The diagnostic performance of tahini SPT and sesame sIgE was assessed by using receiver operating characteristic curve analysis. Results: Of the 49 children included in the study, 21 (42.9%) had a positive tahini-based OFC result. A tahini SPT demonstrated higher predictive performance for OFC positivity compared with sesame sIgE. An optimal cutoff value of 7.5 mm for a tahini SPT result yielded a sensitivity of 81% and a specificity of 85.7%. In contrast, sesame sIgE at a cutoff value of 2.60 kU/L demonstrated lower sensitivity (66.7%) and specificity (82.1%) for predicting OFC outcomes. The sesame sIgE to total IgE ratio was also significantly higher in patients with a positive outcome of OFC (p = 0.049). Patients with a negative outcome of OFC were significantly younger than those with a reactive outcome (p = 0.003). Atopic dermatitis was more prevalent in the negative outcome of the OFC group (p = 0.038), whereas a history of anaphylaxis was not associated with OFC outcomes (p = 0.084). Conclusion: Tahini SPT showed a trend toward better diagnostic performance than did sesame sIgE in predicting clinical reactivity in pediatric SA, although the difference did not reach statistical significance. Younger age and the presence of atopic dermatitis seemed to be associated with a higher likelihood of a negative OFC outcome. However, these findings should be interpreted with caution due to the retrospective design, limited sample size, and single-center setting. Further prospective studies are needed to confirm these observations.