Allergic rhino-conjunctivitis with pollen allergy has been prevalent worldwide and Pollen-food allergy syndrome (PFAS) refers to individuals with pollen allergy who develop oral allergy syndrome (OAS) on consuming fruits and vegetables. The prevalence of PFAS varies by region and that in Japanese adolescents remains to be elucidated. In this cross-sectional study, we examined the epidemiological characteristics of PFAS in a general population of Japanese adolescents according to pollen allergy, OAS, and IgE component sensitization. Participants comprised adolescents, at age 13 years, from a prospective birth cohort study in Japan. We administered questionnaires to collect information from parents regarding pollen allergy, PFAS and OAS at each child’s age 13 years. ImmunoCAP ISAC was used to assess IgE component sensitization. Among 506 participants with a complete questionnaire and ISAC measurement results, 56.5% had a history of hay fever, 16.0% had a history of OAS, 51.0% had pollen allergy, and 11.7% had a history of PFAS; additionally, 72.7% were sensitized to one or more tree, grass, and/or weed allergens. The most common sensitization (95.7%) among adolescents with pollen allergy was to Japanese cedar (Cry j 1). The most common causal foods were kiwi and pineapple (both 39.0%). Knowledge levels about PFAS were poor among affected adolescents. We found a high prevalence of PFAS among adolescents in Japan. Although it affects approximately 1/10 adolescents in the general population, public awareness regarding PFAS is poor. Interventional strategies are needed to increase knowledge and to prevent PFAS in the general population.

Familial hypercholesterolemia (FH) is characterized by a high level of low-density lipoprotein cholesterol (LDL-C) and is inherited as an autosomal dominant trait. We report 4-year-old dichorionic diamniotic twins (boy and girl) with FH who presented with multiple xanthomas on the face, both knees, both feet, and buttocks. Family history revealed vertical transmission of hypercholesterolemia from father to patients, thereby suggesting dominant inheritance. Lipid data of their mother did not match the criteria of FH. However, lipid data of maternal grandmother and maternal sister matched the criteria of FH. LDL receptor gene analysis of the family revealed that their father was heterozygous for a missense mutation, L547V, their mother was heterozygous for a nonsense mutation, C675X, and patients were compound heterozygous for L547V and C675X. After 10 months of treatment with pitavastatin (2 mg/day) and ezetimibe (10 mg/day), LDL-C decreased from 595 mg/dL to 267 mg/dL in the boy and from 530 mg/dL to 182 mg/dL in the girl. These findings suggest that lipid-lowering therapy with statin may be considered in pediatric patients with compound heterozygous FH (hetero FH) before inducing LDL apheresis, and gene analysis for true diagnosis in pediatric patients with multiple xanthomas should be considered, though they appear to be hetero FH from the family history and lipid data of parents.

The oral food challenge test (OFC) is the gold standard for evaluating the remission of food protein-induced enterocolitis syndrome (FPIES). Few acute FPIES remissions confirmed by OFC were reported. This study aimed to examine the OFC for Japanese children with acute FPIES to evaluate its remission. A retrospective cohort study was performed on children with acute FPIES with remission evaluation by OFC based on one food challenge dose (1/50, 1/10, 1/2, and full dose per day). Acute FPIES remission was observed in 65.2% of patients (15/23 patients). Vomiting episodes occurred with 1/50 full doses on the first day among 75% of positive patients. The median duration between the onset and OFC was 14 months (IQR, 8–24 months). Soy was the most common causative food, followed by egg yolk, milk, and wheat. All patients could receive OFC safely without intensive care unit care, based on the FPIES OFC protocol. The remission rate of acute FPIES was high. However, vomiting episodes commonly occurred with 1/50 full doses on the first day. This study suggested that our OFC protocol for acute FPIES was safe and feasible, but it might be safer for some patients to start at a minimal loading dose.

Background: Although hen's egg (HE) allergy was thought to be usually resolved by late childhood, majority of HE allergy patients with a high level of egg white (HEW)-specific IgE could not acquire tolerance for HE by age 8 years.Objective: The aim is to investigate whether the avoidance of HE until 6 years of age increased the risk of heated HE allergy at age 6 years.Methods: This was a retrospective case-control study. The HE tolerance children (n = 17) and children with low-dose HE reactor [a positive reaction to ≤ 4 g of heated HEW in oral food challenges (OFCs)] children (n = 26) were included based on the results of OFC at 6 years old. Multivariate logistic regression analysis was applied to examine the associations between HE avoidance until age 6 years and HE allergy status confirmed by OFC, adjusting the level of ovomucoid-specific IgE (OM-sIgE) during early infancy.Results: A lower proportion of strict avoidance of HE was observed in the HE tolerance group than in the low-dose HE reactor group (6 vs. 46%, p = 0.006). OM-sIgE levels in children younger than 2 years old were significantly higher in the low-dose HE reactor group than those in the HE tolerance group (median [interquartile], 26.7 UA/mL [11.9–53.4] vs. 7.9 UA/mL [0.35–23.4]; p =0.024). The avoidance of HE until 6 years of age increased the risk of heated HE allergy even after adjusting OM-sIgE levels.Conclusions: The long-term avoidance of HE from infancy increased the risk of heated HE allergy confirmed by OFC at age 6 years.

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