Clinical Characteristics of Atopic Dermatitis in Korean School-Aged Children and Adolescents According to Onset Age and Severity

Background: Atopic dermatitis (AD) is a heterogeneous disease with different age of onset, disease course, clinical symptoms, severity, and risk of comorbidity. The characteristics of children with AD also vary by age or country. However, little is known about the clinical characteristics of AD in Korean school-aged children and adolescents. Furthermore, there are few studies on phenotypic differences according to onset age. This study aimed to explore the clinical characteristics and phenotypes according to onset age and severity of AD in children and adolescents in Korea.Methods: AD patients aged 6–18 years who presented to 18 hospitals nationwide were surveyed. The patients were examined for disease severity by pediatric allergy specialists, and data on history of other allergic diseases, familial allergy history, onset age, trigger factors, lesion sites,treatment history and quality of life were collected. The results of the patient’s allergy test were also analyzed. The patients were classified into infancy-onset (< 2 years of age), preschoolonset(2–5 years of age), and childhood-onset (≥ 6 years of age) groups. Study population wasanalyzed for clinical features according to onset-age groups and severity groups.Results: A total of 258 patients with a mean age of 10.62 ± 3.18 years were included inthe study. Infancy-onset group accounted for about 60% of all patients and presentedsignificantly more other allergic diseases, such as allergic rhinitis and asthma (P = 0.002and P = 0.001, respectively). Food allergy symptoms and diagnoses were highly relevant toboth earlier onset and more severe group. Inhalant allergen sensitization was significantlyassociated with both infancy-onset group and severe group (P = 0.012 and P = 0.024,respectively). A family history of food allergies was significantly associated with infancyonsetgroup (P = 0.036). Severe group was significantly associated with a family historyof AD, especially a paternal history of AD (P = 0.048 and P = 0.004, respectively). Facial(periorbital, ear, and cheek) lesions, periauricular fissures, hand/foot eczema, and xerosiswere associated with infancy-onset group. The earlier the onset of AD, the poorer the qualityof life (P = 0.038). Systemic immunosuppressants were used in only 9.6% of the patients inthe severe group.Conclusion: This study analyzed the clinical features of AD in Korean children andadolescents through a multicenter nationwide study and demonstrated the phenotypicdifferences according to onset age and severity.