The diet must be followed for a set time period, at least until a significant symptom pattern (recurrence or relief) is appreciated: this might be, on average, 2–4 weeks for classical IgE-mediated symptoms, while longer periods, up to 6 weeks, would be required for investigating non-IgE-mediated presentations (see below), as in eosinophilic esophagitis (EoE). Here, IGHE is linked to eosinophilic esophagitis.