Clinical Characteristics of Oral Allergy Syndrome in Children with Atopic Dermatitis and Birch Sensitization: a Single Center Study

BACKGROUND: Oral allergy syndrome (OAS) is an immunoglobulin E (IgE)-mediated hypersensitivity that occurs frequently in older children with pollen sensitization. This study focused on the clinical characteristics of OAS in children with atopic dermatitis (AD) and birch sensitization. METHOD: s: A total of 186 patients aged 2–18 years with AD and birch sensitization were enrolled in this study between January 2016 and March 2017. Their levels of serum total IgE and birch- and ragweed-specific IgE (sIgE) were measured using ImmunoCAP (Thermo Fisher Scientific, Uppsala, Sweden). Information regarding causative foods and symptoms were obtained via interviews. The patients were divided into 3 groups according to their ages (group 1, 2–6 years; group 2, 7–12 years; and group 3, 13–18 years). RESULTS: Eighty-one of the 186 (43.5%) children with AD who were sensitized to birch pollen were diagnosed as having OAS. The prevalence of OAS in group 1 (the children who had AD and birch sensitization aged 2–6 years) was 36.6%. A greater predominance of men was noted in the non-OAS group (77.1%) compared to the OAS group (60.5%). Apples were the most common causative food in group 2 and 3 while kiwis were the most common cause of OAS in group 1. There was a statistically significant correlation between birch-sIgE levels and the prevalence of OAS (P = 0.000). The cut-off value was 6.77 kU(A)/L with 55.6% sensitivity and 79.0% specificity (area under the curve 0.653). CONCLUSION: In our study, the prevalence of OAS in children with AD and birch sensitization was 43.5%. Even in the preschool age group, the prevalence of OAS was considerable. Patients with high levels of birch-sIgE were more likely to have OAS. Clinicians should therefore be vigilant about OAS in patients with a high degree of sensitization to birch pollen and even young children if they have birch sensitization.