Low-Dose Oral Food Challenge with Hazelnut: Efficacy and Tolerability in Children

Hazelnut allergy (HA) is one of the more common food allergies (FAs) in Europe with a prevalence of 0.2%. The gold standard for diagnosing FA is oral food challenge (OFC) with the culprit food. Another purpose of OFC is to identify the "threshold level" of food as the dose that elicits symptoms. In this way it is possible to avoid a strict elimination diet and to determine the minimal quantity of the culprit food tolerated by the patient.

The aim of our study was to assess the efficacy and tolerability of hazelnut low-dose OFC (H-LDOFC) in children with HA.

From January 2015 to December 2016, we retrospectively analyzed the charts of patients referred to Allergy Unit of Meyer Children's Hospital, Florence, Italy for a history of HA. Prick by prick (PbP) and specific serum IgE (s-IgE) to hazelnut were performed. We proposed conducting an H-LDOFC to parents of children with HA. The H-LDOFC was considered completed when a cumulative dose of 2.5 g of hazelnut was reached. We divided the patients who underwent the H-LDOFC into an asymptomatic and a symptomatic group. For statistics we used SPSS for Windows version 16.0 and conducted a t test for comparing the averages, considering a p value of < 0.05 significant.

Forty-three out of 70 patients (61.4%) with HA underwent an H-LDOFC. The PbP to hazelnut (mean ± SD) was 7.2 ± 2.9 mm and the s-IgE to hazelnut 25.3 ± 32.5 kU/L. Twenty-eight out of the 43 patients (65.1%) who underwent H-LDOFC reached the cumulative dose of 2.5 g of hazelnut. During the H-LDOFC, 20/43 patients (46.5%) had no reactions and 23/43 patients had a total of 55 reactions: 34 (61.8%) oral allergy syndrome, 8 (14.5%) rash, 6 (10.9%) abdominal pain, 2 (3.6%) urticaria, 2 (3.6%) angioedema, and 3 (5.4%) dyspnea. Atopic dermatitis was found to present the only statistically significant difference (p = 0.002) in patients with symptoms compared to asymptomatic patients during H-LDOFC.

To our knowledge, this was the first study to assess the efficacy and tolerability of H-LDOFC in a pediatric population. Our study suggests that in children with HA, H-LDOFC is well accepted and safe because adverse reactions are mild and the majority are represented by localized symptoms (oral allergy syndrome) and efficient, especially in terms of improvement of quality of life. For these reasons it could be more extensively used in the treatment of HA.