4.3 Patients will be grouped by OFC their allergy status result for each tree-nut (patients with a documented IgE-mediated reaction in the previous year or a positive OFC vs. patients with regular consumption of the index food or a negative OFC). Descriptive statistics (proportions for categorical variables, means or medians and standard deviations or inter-quartile range for continuous variables) will be reported for all key participant variables, including baseline and demographic characteristics, SPT, BAT and component testing results.