Elevated serum bilirubin in neonates may serve as an early indicator of later neurodevelopment after birth. This study examined the connection between neonatal jaundice requiring phototherapy and later neurodevelopment. This retrospective population-based cohort included 3,203,983 children born in Korea from 2009 to 2015, tracked from birth until December 2021 in Korea. Neurodevelopmental outcomes at 66–71 months of age were assessed using national child health screening data. Analyses controlled for confounders including sex, birth weight, prematurity, chromosomal abnormalities, congenital malformations, income, and infant feeding type. Neurodevelopmental outcomes were evaluated in six domains (gross motor, fine motor, cognition, language, social skills, and self-help) using the Korean Developmental Screening Test (K-DST). Effect of phototherapy duration on each domain was also examined. A total of 1,004,385 neonates were included, of whom 121,366 (56.0

Atopic dermatitis is associated with mental health and epileptic seizure in adults, which are attributed to inflammatory cytokine dysregulation, resulting in neuromodulatory dysfunction and neuronal hyperexcitability. The aim of the study is the investigation the potential association between atopic dermatitis and febrile seizure in young children. Data of children born in Korea were obtained from the National Health Insurance Service claims database, which is linked to the National Health Screening Program for Infants and Children database. We analyzed health insurance data at birth from 2008 to 2012 who were followed up until December 31, 2018. The exposure was atopic dermatitis, defined operationally in NHIS claims data as ≥ 5 L20.x diagnoses and ≥ 2 topical corticosteroid prescriptions during the study period; the primary outcome was febrile seizure (ICD-10 codes R56.00 and R56.01) occurring after the index date between 6 months and 6 years of age. The exposed cohort comprised 69,238 children, who were matched with an unexposed cohort of the same size. The median age at atopic dermatitis diagnosis was 2.5 months, and 49.5

Purpose: Treatment responses to Mycoplasma pneumoniae (MP) pneumonia in children exhibit considerable variability. It is essential to identify predictive indicators and elucidate mechanisms associated with treatment responses. This study aimed to characterize the clinical, radiological, laboratory, and cytokine profiles associated with treatment responses in pediatric MP pneumonia. Methods: A retrospective analysis was performed in 85 children hospitalized with MP pneumonia between May 2019 and March 2020. Patients were categorized into the good response group (n= 74) or the poor response group (n= 11) based on clinical responses to step-wise treatment. Clinical characteristics, radiological findings, laboratory parameters, and serum levels of 27 cytokines obtained at admission were compared between the groups. Results: Compared to the good response group, the poor response group exhibited significantly longer fever duration (11.36 +/- 5.33 days vs. 5.77 +/- 3.95 days, P= 0.006), more frequent lobar consolidation (63.6% vs. 20.3%, P= 0.043), and higher lactate dehydrogenase levels (1,146 +/- 505 IU/L vs. 731 +/- 231 IU/L, P= 0.008) and MP-specific immunoglobulin M index (6.49 +/- 3.01 vs. 3.85 +/- 3.28, P= 0.014). Among the cytokines assessed, IL-21, IL-22, and IL-31 levels were significantly elevated in the good response group. IL-17A levels were also higher in this group, albeit not statistically significant. Conclusion: Early identification of clinical, laboratory, and radiologic markers may facilitate early prediction of treatment response in pediatric MP pneumonia. Elevated IL-21, IL-22, and IL-31 levels in the good response group suggest a potential role forTh17-related cytokine activity in favorable treatment outcomes, warranting further investigation in larger cohorts. (Allergy Asthma RespirDis 2026; 14:14-19)

BackgroundThe COVID-19 pandemic disrupted the seasonal patterns of pediatric respiratory infections, likely due to an immunologic gap. However, the roles of weather conditions and viral interactions in age-specific transmission, seasonality, and coinfections remain unclear.MethodsThis retrospective study analyzed data from children hospitalized with respiratory tract infections between January 2012 and December 2023 at a single tertiary center in Korea. Six common respiratory viruses were identified via multiplex polymerase chain reaction (PCR). The study period was divided into prepandemic (January 2012 to January 2020), pandemic (February 2020 to November 2021), and postpandemic (December 2021 to December 2023) periods. Pandemic-period patients (n = 171) were excluded from comparative analyses. Virus positivity, coinfection rates, and demographic differences were assessed using chi-square tests and t-tests. Time-series analysis using seasonal autoregressive integrated moving average models (SARIMA and SARIMAX) was conducted to compare observed and predicted trends.ResultsAmong 12,306 hospitalized children, 86.3% were in the prepandemic period and 12.3% in the postpandemic period. Median age rose from 20.0 to 27.0 months. Rhinovirus (21.3%-43.7%) and human metapneumovirus (6.6%-9.6%) increased, while influenza declined (4.8%-2.8%). Seasonal patterns shifted, with higher positivity in summer and autumn. Observed trends diverged from SARIMAX predictions, suggesting changes not fully explained by the meteorological variables included in the model. Coinfections with three or more viruses rose (1.7%-3.0%), and virus-negative proportions decreased (32.6%-16.7%). RSV showed three peaks in the postpandemic period, suggesting possible shifts in viral cocirculation patterns.ConclusionShifts in pediatric respiratory virus patterns were observed in the postpandemic period and were not fully explained by meteorological variables alone, highlighting the need for adaptive surveillance incorporating broader environmental and demographic factors.

Background/Objectives: Atopic dermatitis (AD) and food allergy (FA) frequently coexist in the concept of atopic march; however, their combined associations with psychological problems remain poorly understood. This study aimed to investigate the associations of AD and FA with psychological outcomes at age 7 and evaluate whether respiratory allergies account for part of these associations. Methods: We enrolled 1577 children aged 7 years from the Panel Study of Korean Children. The Korean version of the Child Behavior Checklist was used to assess psychological and behavioral problems. Multivariable regression and parallel mediation analyses were used to evaluate independent and interactive associations. Results: AD and FA were associated with psychological and behavioral problems, most consistently with somatic problems on the Diagnostic and Statistical Manual of Mental Disorders (DSM)-oriented scale. These associations were more pronounced in children with comorbid AD and FA than in those with single allergies. Among the 9 children with concurrent AD and FA, an interaction between the two conditions on somatic problems was observed (P for interaction = 0.033). The comorbid group showed higher eosinophil counts and total IgE levels, but no differences in SCORAD indices or C-reactive protein levels. Mediation analysis identified a direct association of AD with somatic problems (B = 1.062; 95% CI, 0.601–1.562), with a portion accounted for by allergic rhinitis (AR) (B = 0.656; 95% CI, 0.306–1.241). Conclusions: Comorbid AD and FA were associated with higher odds of somatic problems than either condition alone in 7-year-old children, with a portion of the AD association accounted for by AR. Because exposures and outcomes were assessed concurrently, these associations are exploratory and hypothesis-generating rather than causal. Clinical attention may be warranted for children with both AD and FA.

PURPOSE:This study assessed the prevalence, major triggers, and risk factors of food allergy (FA) and food-induced anaphylaxis among Korean school-aged children. METHODS:In 2022, a nationwide school-based survey was conducted using a structured questionnaire. Cluster sampling yielded a representative sample of 12,558 students aged 6-7, 9-10, and 12-13 years from 213 elementary and 103 middle schools in Korea. RESULTS:The prevalence of self-reported perceived FA was 15.3%; recurrent immediate-type (< 4 hours) FA, 7.8%; and physician-diagnosed FA, 5.5%, with food-induced anaphylaxis in 0.7% of cases. The leading allergens for recurrent immediate-type FA were peach (1.13%), milk (0.82%), egg (0.79%), kiwi (0.65%), walnut (0.62%), peanut (0.62%), apple (0.61%), crab (0.59%), shrimp (0.54%), and pineapple (0.33%). By food group, fruits (3.67%) were most frequent, followed by crustaceans (1.20%), and tree nuts (1.18%). Major anaphylaxis triggers included egg (0.19%), milk (0.11%), walnut (0.10%), peanut (0.09%), and peach (0.06%). Fruit allergy was more common in older age groups, accompanied by increased oral allergy symptoms, suggesting a rising burden of pollen FA syndrome. In these groups, crustaceans were also major allergens. Among tree nuts, walnut was the most common. Perilla seed, a uniquely observed allergen in Korea, had prevalences of 0.11% for allergy and 0.02% for perilla seed-induced anaphylaxis. Multiple food allergies were reported by 29.9% of children with FA. Significant risk factors included paternal allergic disease, parental history of FA, delayed complementary food introduction (≥ 7 months), prolonged breastfeeding (≥ 7 months), and current allergic diseases, particularly atopic dermatitis. CONCLUSIONS:In Korean school-aged children, recurrent immediate-type FA and food-induced anaphylaxis affect 7.8% and 0.7%, respectively. Fruits, milk, egg, tree nuts, and peanuts are the most common triggers, with notable age-related differences. These findings underscore the need for continued surveillance, early identification of high-risk groups, and targeted prevention and management strategies.

Background: Congenital diaphragmatic hernia (CDH) is a rare but serious congenital anomaly linked to high mortality rates and significant long-term morbidity. Although numerous prognostic factors for short-term outcomes have been identified through hospital-based studies, data on long-term mortality at the population level are limited. Specifically, nationwide assessments of long-term outcomes for infants with CDH are scarce. This study aimed to estimate the national 5-year all-cause mortality for CDH and to create a population-level risk stratification nomogram utilizing nationwide health insurance claims data. Methods: We conducted a retrospective cohort study of infants with CDH using nationwide insurance claims data from 2002 to 2016, allowing for complete 5-year follow-up. We analyzed population-level demographic and clinical proxy variables with Cox proportional hazards models and developed a nomogram for long-term mortality risk stratification. Results: Factors such as rural residence, middle-to-high SES, respiratory distress in newborns, and CHD were associated with increased 5-year mortality in infants with CDH. The claims-based nomogram, which incorporated sociodemographic and comorbidity variables, demonstrated moderate discriminatory power (AUC 0.76; C-index 0.78) for population-level risk stratification. Conclusions: This nationwide claims-based cohort study provides population-level estimates of 5-year mortality associated with CDH and introduces a nomogram that offers moderate discriminatory ability for long-term risk stratification.

Rhinoviruses are the most prevalent respiratory viruses across age groups, responsible for a wide spectrum of illnesses ranging from mild upper respiratory symptoms to lower airway involvement. Moreover, rhinovirus infection is also a major driver of asthma exacerbation and development, imposing a substantial disease burden. Rhinoviruses are classified into three species: RhinovirusA, Rhinovirus B, and Rhinovirus C, each utilizing distinct host cell receptors and exhibiting different clinical patterns. RhinovirusA and Rhino-virus Care more frequently associated with clinically significant disease outcomes compared to Rhinovirus B. Rhinovirus C binds to cadherin-related family member 3 (CDHR3), and a missense variant in CDHR3 (rs6967330) increases epithelial expression of the receptor, enhancing susceptibility to infection and severe illness, particularly in early life. Rhinovirus infection induces complex immune responses, characterized by impaired interferon signaling, type 2 inflammation, and epithelial barrier disruption. In individuals with asthma, altered interferon responses and T2-high immune profiles are closely linked to rhinovirus-induced exacerbations. In infants with atopic traits, such as eosinophilia, allergen sensitization, or a family history of allergic diseases, rhinovirus infection is strongly associated with subsequent development of asthma. Rhinovirus vaccine is needed to prevent severe respiratory infections and asthma exacerbations, particularly in vulnerable populations. Rhinovirus vaccine development has been challenging due to extensive antigenic diversity and limited cross-protective immunity. Recent progress in high-valency inactivated vaccines has demonstrated the feasibility of eliciting broad neutralizing responses. Prioritizing rhinovirus types linked to greater clinical severity may enable targeted vaccine strategies for high-risk populations, offering a promising approach to reducing the global burden of rhinovirus-associated illnesses. (Allergy Asthma Respir Dis 2026;14:69-76)

BACKGROUND:Antibiotic resistance is a global health concern, driven by inappropriate use. Contemporary data on antibiotic prescribing patterns for pediatric upper respiratory infections (URIs) are needed to evaluate trends and guide stewardship efforts. We examined longitudinal trends in antibiotic prescribing for pediatric URIs in South Korea, stratified by antibiotic class and patient age group. METHODS:We conducted a retrospective study using the National Health Insurance Service (NHIS) pediatric sample cohort in South Korea (2002-2019). The dataset included 639,702 outpatient visits with a primary URI diagnosis among 369,702 children < 18 years. Children with complex chronic conditions were excluded, and antibiotic prescriptions were grouped into six classes. Primary outcomes were the antibiotic prescribing rate (per URI visit) and antibiotic exposure days (per 1000 person-years), stratified by age group and antibiotic class. Temporal trends were assessed using joinpoint regression to estimate annual percent change (APC) and average annual percent change (AAPC). RESULTS:The proportion of antibiotic prescriptions for pediatric URIs declined from 80.2 % to 49.1 % (APC -0.27 % per year; 95 % CI -0.62-0.04). Narrow-spectrum penicillin use decreased, macrolide remained relatively stable, and broad-spectrum penicillin initially increased and later stabilized. Antibiotic exposure days per 1000 person-years increased overall (AAPC 1.88 %, 95 % CI 1.59-2.21), with the highest exposure in children aged 1-5 years, peaking around 2008 before gradually declining. Other age groups were largely stable. CONCLUSION:Antibiotic prescribing declined modestly overall, while broad-spectrum penicillin increased and narrow-spectrum agents decreased, with exposure highest in children aged 1-5 years. Sustained outpatient stewardship is needed to reduce unnecessary use and prioritize narrow-spectrum therapy when indicated.

Childhood allergic diseases and asthma have their origins in early life, and allergen exposures during this period could be a critical determinant of the progression to tolerance versus disease. Mechanisms for sensitization may be different but overlapping for food and aeroallergen sensitization in children. This suggests differences in how exposure to food and aeroallergens influence allergic sensitization. For food allergy, introducing foods such as peanut and egg proteins into the diet at an early age reduces the risk of peanut and egg allergy, respectively, across a broad demographic, whereas evidence is less established for other foods. The relationship between allergen exposure and sensitization to aeroallergens is more complex but critical, given the close relationship between specific immunoglobulin E and respiratory disease. Several factors could mediate the progression from allergen exposure and allergic sensitization versus tolerance, including epithelial barrier function and altered immune development at the skin and mucosal surfaces, exposure to irritants and pollutants, and genetic susceptibility. Collectively, the current evidence base provides a compelling rationale for the primary prevention of food allergy by introducing common allergens such as peanut and egg early. In contrast, primary prevention of aeroallergen sensitization is more complex and perhaps more challenging to achieve by manipulating allergen exposures. Even so, recent advances in understanding how the microbiome and environmental toxins and irritants modulate the mucosal immune response have identified potential new strategies for primary prevention of food and aeroallergen sensitization.

PURPOSE:This study aimed to assess the current prevalence of allergic rhinitis (AR) among Korean children based on a 2022 nationwide survey and to analyze long-term trends from 1995 to 2022. METHODS:A nationwide cross-sectional study was conducted in 2022, involving 12,558 children aged 6-13 years from randomly selected elementary and middle schools across Korea. The AR prevalence and risk factors were assessed using the modified International Study of Asthma and Allergies in Childhood Questionnaire. The data were compared with epidemiological surveys conducted in 1995, 2000, and 2010 to evaluate long-term trends. RESULTS:The prevalence rates of AR symptoms during the last 12 months were 45.2%, 48.2%, and 47.8%, respectively, in children aged 6-7, 9-10, and 12-13 years, respectively. Among children aged 6-7 years, the prevalence of AR symptoms showed a long-term upward trend, rising from 29.9% in 1995 to 26.0% in 2000, 43.6% in 2010, and 45.2% in 2022 (P < 0.001). Among children aged 12-13 years, the prevalence rates also increased steadily, from 26.7% in 1995 to 31.0% in 2000, 42.7% in 2010, and 47.8% in 2022 (P < 0.001). A parental history of allergic disease and a diagnosis of atopic dermatitis were risk factors for AR symptoms during the last 12 months across all study populations from both the 2010 and 2022 surveys. Antibiotic use during infancy and male sex were significant contributors to AR development in children aged 6-7 years, whereas female sex was a significant risk factor in adolescents aged 12-13 years in 2022. CONCLUSIONS:The prevalence of AR among Korean children has increased over the past few decades, highlighting the importance of continuous surveillance and preventive measures. Identifying modifiable risk factors, such as early-life exposure and environmental influences, is crucial for developing targeted intervention strategies.

The incidence of chronic urticaria has risen significantly in Korea, particularly among children and women, as revealed by an 18-year cohort study using the Korean Health Insurance database. These findings emphasize the importance of enhanced clinical management and increased awareness of chronic urticaria's growing impact.

Background: An understanding of the phenotypes and endotypes of atopic dermatitis (AD) is essential for developing precision therapies. Recent studies have demonstrated evidence for the gut-skin axis in AD . Objective: We sought to determine the natural course and clinical characteristics of AD phenotypes and investigate their mechanisms on the basis of multiomics analyses. Methods: Latent class trajectory analysis was used to classify AD phenotypes in 2247 children who were followed until age 9 years from the COhort for Childhood Origin of Asthma and allergic diseases birth cohort study. Multiomics analyses (microbiome, metabolites, and gut epithelial cell transcriptome) using stool samples collected at age 6 months were performed to elucidate the underlying mechanisms of AD phenotypes. Results: Five AD phenotypes were classified as follows: never/ infrequent, early-onset transient, intermediate transient, late- onset, and early-onset persistent. Early-onset persistent and late-onset phenotypes showed increased risks of food allergy and wheezing treatment ever, with bronchial hyperresponsiveness evident only in the early-onset persistent phenotype. Multiomics analyses revealed a significantly lower relative abundance of Ruminococcus gnavus and a decreased gut acetate level in the early-onset persistent phenotype, with potential associations to ACSS2, Janus kinase-signal transducer and activator of transcription signaling, and systemic TH2 inflammation. The early-onset transient phenotype was associated with adenosine monophosphate-activated protein kinase (AMPK) and/or chemokine signaling regulation, whereas the late-onset phenotype was linked with IL-17 and barrier dysfunction. Conclusions: Multiomics profiling in early life may offer insights into different mechanisms underlying AD phenotypes in children. (J Allergy Clin Immunol 2025;155:557-68.)

BACKGROUND The effect of probiotics in the treatment of atopic dermatitis (AD) is inconclusive, partially due to the heterogeneities of AD. OBJECTIVE The aim of the present study was to investigate the efficacy of probiotics in the treatment of AD with a subgroup analysis according to country, severity of AD, duration of supplementation, and probiotic strain. METHODS Original articles reporting the therapeutic efficacy of probiotics for AD were identified by searching PubMed, Cochrane Library databases, and Embase from inception to September 30, 2022. RESULTS This meta-analysis included 1,382 patients with AD from 25 randomized controlled trials. Probiotic supplementation was effective for the treatment of AD, reflected in a significant decrease in the SCORing Atopic Dermatitis (SCORAD) index (SMD, -4.0; 95%CI, -7.3 to -0.7). The subgroup analysis showed a significant therapeutic effect for AD among patients with mild or moderate AD (SMD, -1.4; 95%CIs -2.2 to -0.7), in those supplemented for more than three months (SMD, -5.1; 95%CIs -9.7 to -0.4), and in those supplemented with a probiotic that contained Lactobacillus spp. strains combined with or without other strains (SMD, -4.4; 95%CIs -8.0 to -0.8). In addition, the therapeutic effects of probiotics showed differences according to country and geographic region. CONCLUSIONS Probiotics can be beneficial for the treatment of AD, and their therapeutic effect may be individually tailored to improve it based on the severity of AD, strain of probiotics, duration of supplementation, and geographic region.

PURPOSE:We investigated the prevalence of asthma and its risk factors in Korean children in 2022, comparing the prevalence with previous data to identify trends in the prevalence of childhood asthma over time. METHODS:This nationwide cross-sectional study enrolled 4,038 children aged 6-7 years and 4,269 children aged 12-13 years from 213 randomly selected elementary schools in 2022. The prevalence of asthma in 2022 was compared with those in 1995, 2000, and 2010, with subgroup comparisons classified by gender. A modified International Study of Asthma and Allergies in Childhood questionnaire assessed asthma prevalence with environmental factors. RESULTS:The prevalence of ''asthma diagnosis ever' in children aged 6-7 years was 9.1%, 9.4%, and 10.4% in 1995, 2000, and 2010, respectively, which was decreased in 2022 (2.1%, P < 0.001). The prevalence of 'current asthma' in children aged 6-7 years showed fluctuations (3.5%, 2.0%, 4.2%, and 0.6% in 1995, 2000, 2010, and 2022, respectively) without showing a significant trend. The prevalence of 'asthma diagnosis ever' and 'current asthma' in children aged 6-7 years was significantly higher in males than in females. The prevalence of 'asthma diagnosis ever' in children aged 12-13 years was 3.1% in 1995, with a significant increasing trend in 2000 (5.8%) and 2010 (7.5%), followed by a decrease in 2022 (3.4%). Male sex, a history of bronchiolitis in early life, allergic rhinitis diagnosis ever, and atopic dermatitis diagnosis ever were associated with 'asthma diagnosis ever' in children aged 6-7 years. For children aged 12-13 years, male sex and history of bronchiolitis in early life were independently associated with 'asthma diagnosis ever.' CONCLUSIONS:Childhood asthma prevalence has decreased, varying by asthma definition. The study's findings provide important information for establishing prevention and management strategies of childhood asthma.

Atopic dermatitis is the most common chronic inflammatory skin disease in children and adolescents. The Korean Academy of Pediatric Allergy and Respiratory Disease published the Atopic Dermatitis Treatment Guideline in 2008, which has been helpful in atopic dermatitis treatment until now. Various reports on the development and effectiveness of new drugs have suggested that there is a need to develop and revise old treatment guidelines. Part 1 aimed to provide evidence-based recommendations for skin care management and topical treatment for atopic dermatitis. Part 2 focuses on systemic treatment, novel therapeutics, and adjuvant therapy. The goal of this guideline is intended to assist front-line doctors treating pediatric and adolescent atopic dermatitis patients make safer, more effective, and more rational decisions regarding systemic treatment, novel therapeutics, and adjuvant therapy by providing evidence-based recommendations with a clear level of evidence and benefit regarding treatment.