D1.238 - Natural history of early onset atopic dermatitis and risk factors for persistency using Korean National Health Service data

The natural history of early-onset atopic dermatitis (AD) remains incompletely understood, particularly regarding its persistence into adolescence and the influence of comorbid atopic diseases.

This study investigated the longitudinal course of early-onset AD and identified risk factors associated with its persistence in a nationwide population-based cohort. Using the Korean National Health Insurance Service database, we conducted a longitudinal study of children diagnosed with AD (ICD-10 code L20) as a primary diagnosis on at least two occasions before age 2 between 2008 and 2017. Patients with congenital diseases, chromosomal abnormalities were excluded. Participants were followed up until 2022 to assess disease persistence based on annual AD-related healthcare visits. Cox proportional hazards models were used to evaluate risk factors.

A total of 1,295,787 children were included in the final analysis. Among children with early-onset AD, 13.8%, 9.0%, and 1.2% continued to receive AD-related care at ages 5, 10, and 14 years, respectively. Significant risk factors for persistence included female sex, earlier calendar year of diagnosis (before 2010), older age at diagnosis, lower socioeconomic status, and residence in Seoul. Comorbid food allergy and asthma were also identified as independent risk factors for persistence.

In this nationwide cohort of over 1.2 million children, most cases of early-onset AD cases achieved remission by adolescence. However, persistence was significantly linked to specific demographic and socioeconomic factors, as well as allergic comorbidities. These findings highlight the need for targeted management strategies in high-risk groups to mitigate the long-term burden of AD.