Background: Causes of pediatric pollen food allergy syndrome (PFAS) differ depending on airborne pollen levels in a particular region. We aimed to analyze airborne pollen counts, IgE sensitization rates, and PFAS incidence among children with allergies in South Korea and Japan. Methods: This cross-sectional study included children aged 5–17 years with allergies in 2017. Airborne pollen samples were collected from Busan in South Korea, and Fukuoka and Tochigi in Japan. Questionnaires were used to assess bronchial asthma, seasonal allergic rhinitis, atopic dermatitis, food allergy, and PFAS. The serum IgE specific to Dermatophagoides pteronyssinus, pollen, tomato, and peach were investigated. Results: In total, 57, 56, and 20 patients from Busan, Fukuoka, and Tochigi, respectively, were enrolled. Airborne Japanese cedar and cypress pollen were predominant in Fukuoka and Tochigi, whereas pine and alder pollen were predominant in Busan. Children with allergies in Fukuoka and Tochigi had a significantly higher sensitization rate to Japanese cedar, cypress, juniper, orchard grass, ragweed, Japanese hop, and tomato compared with children in Busan. In Fukuoka and Tochigi, where Japanese cedar and cypress pollen were frequently scattered, high sensitizations among allergic children were observed. The sensitization rate was not affected by the pollen count in alder, grass, ragweed, and Japanese hop. In multivariable analysis, only alder sensitization was found to be associated with PFAS (odds ratio: 6.62, 95% confidence interval: 1.63–26.87, p = 0.008). In patients with PFAS in Busan and Tochigi, peach associated with birch allergen Bet v 1 was a causative food item for PFAS. Moreover, PFAS was associated with ragweed and Japanese hop pollen sensitization in Fukuoka. Conclusion: Regardless of pollen counts, alder pollen sensitization was associated with PFAS in children. Ragweed and Japanese hop pollen sensitization were associated with PFAS, particularly among children in southern Japan.

Objective: The relationship between exercise-induced bronchoconstriction (EIB) and exertional dyspnea in children and adolescents is yet to be fully established. This study examined whether indicators of fractional exhaled nitric oxide (FeNO), forced expiratory volume in 1 s (FEV₁) percent predicted at baseline, and dyspnea are useful for predicting children and adolescents with EIB. Methods: We enrolled 184 children and adolescents diagnosed with asthma (mean age 11.2 years); participants were divided into two groups according to age (12 years) and were subjected to a 6-min exercise challenge test. Lung function tests and modified Borg scale scores were used to examine perceptions of dyspnea at 0, 5 and 15 minutes after exercise. Results: Among children, the maximum percentage drop in FEV₁ after exercise correlated significantly with FeNO (adjusted β = 2.3, P < 0.001) and with the perception of dyspnea at 5 minutes after exercise (adjusted β = 1.9, P < 0.001). Among adolescents, the maximum percentage drop in FEV₁ correlated with FeNO (adjusted β = 2.7, P = 0.007) and with lung function (FEV₁, percent predicted; adjusted β = −0.28, P = 0.006). Children with EIB had significantly stronger dyspnea after exercise than did children without EIB. Adolescents even without EIB may experience more exertional dyspnea than children without EIB. Conclusions: Overall, our findings indicated that EIB was associated with FeNO and exertional dyspnea in asthmatic children. By contrast, EIB was associated with FEV₁ percent predicted at baseline and FeNO but not with exertional dyspnea in asthmatic adolescents.

Background: Childhood asthma is a major risk for low lung function in later adulthood, but what factors in asthma are associated with the poor lung function during childhood is not known. Objective: To identify clinical factors in children with asthma associated with low or declining lung function during the treatment. Methods: We enrolled children with asthma who had been treated throughout three age periods, i.e., 6–9, 10–12, and 13–15 years old, at seven specialized hospitals in Japan. Clinical information and lung function measurements were retrieved from the electronic chart systems. To characterize the lung function trajectories during each age period, we evaluated the forced expiratory volume 1 (FEV1) with % predicted values and individual changes by the slope (S) from linear regression. We defined four trajectory patterns: normal (Group N) and low (Group L), showing %FEV1 ≥80% or <80% throughout all three periods; upward (Group U) and downward (Group D), showing S ≥ 0 or S < 0%. Logistic regression analysis was performed to compare factors associated with the unfavorable (D/L) versus favorable (N/U) groups. Results: Among 273 eligible patients, 197 (72%) were classified into Group N (n = 150)/U (n = 47), while 76 (28%) were in Group D (n = 66)/L (n = 10). A history of poor asthma control, long-acting beta2 agonist use, and a lower height Z-score during 13–15 years were associated with an unfavorable outcome (Group D/L). Conversely, inhaled corticosteroid (ICS) use during 10–12 years and high-dose ICS use during 13–15 years were associated with a favorable outcome (Group N/U). Conclusion: We identified several factors that are associated with unfavorable lung function changes in pediatric asthma. Attention should be paid to the possible relationship between yearly changes in lung function and poor asthma control, use of ICS (and its dose) and use of LABA.

Background: Exercise-induced anaphylaxis (EIA) is a rare and potentially life-threatening disorder that can develop independently without food ingestion. Cold drinks can also trigger symptoms in some patients with cold-induced anaphylaxis. We present a case of a patient with EIA that was diagnosed on the basis of positive exercise loading test with hyperleukotrieneuria. Case presentation: A 12-year-old girl presented with acute flushing, cyanosis, swollen eyelids, and dyspnea after an endurance run in winter or swimming in a cold-water pool. She also developed dyspnea after having a cold drink. She had no history of food allergies, atopy, or asthma. No association was noted between anaphylaxis and food intake in her history. On the first day, she ingested 200 mL of 5 °C cold water in 30 s, which did not trigger symptomatic responses, but her urinary leukotriene E4 (LTE4) level increased (pre-challenge test: 295 pg/mg-creatinine (cr), post-challenge test: 400 pg/mg-cr). On the second day, she underwent the exercise loading test according to the Bruce protocol by using an ergometer to increase the power of exercise every 2 min. She had been fasting for > 15 h and did not have breakfast. Just after the exercise loading test, the plasma adrenaline and noradrenaline increased. At 15 min after the exercise loading test, her plasma adrenaline and histamine (pre-challenge test: 0.7 ng/mL, 15 min post-challenge test: 81 ng/mL) rose sharply with anaphylaxis symptoms accompanied by increasing urinary LTE4 (pre-challenge test: 579 pg/mg-cr, post-challenge test: 846 pg/mg-cr). After she was discharged, she was restricted from strenuous exercise especially in cold environments and prescribed an adrenaline autoinjector. Conclusion: Cold stimulation can become a co-effector of EIA. Measurements of urinary LTE4 levels during challenge testing are useful for diagnosing EIA and capture the pre-anaphylaxis stage.

Motomura C, et al. Asia Pac Allergy. 2022 Apr;12:e14. https://doi.org/10.5415/apallergy.2022.12.e14