Methods: A retrospective analysis of oral food challenge (OFC) results of patients with a clinical history of peanut allergy and a positive skin prick test (≥ 3 mm wheal) and/or patients enrolled in a peanut oral immunotherapy (OIT) program was performed. A physician-supervised OFC was administered starting with a dose of 0.1 mg of peanut protein followed by subsequent dose escalations, until a reaction occurred.
Results: OFCs were performed in 137 patients (ages 10 months to 35 years, median 7 years), the majority of which (115/137) entered our OIT program. 15/137 (10.9%) reacted at 5 mg or less and 68/137 (49.6%) reacted at 25 mg or less. The lowest observed adverse effect level (LOAEL) value was 1.25 mg (n=3) and the no-observed adverse effect level (NOAEL) was 1 mg (n=137). No subjects were left-censored.
Conclusions: The LOAEL found in patients in Israel, a country with a lower peanut allergy prevalence rate is significantly higher than values published in worldwide pooled data. These data if confirmed suggest that NOAEL established in countries with "high" peanut allergy prevalence may be utilized universally.