Key Points Question Is the incidence rate of pediatric atopic dermatitis still increasing? Findings In this cohort study, all children resident in Norway younger than 6 years from January 1, 2009, through December 31, 2015, were included. The overall incidence rate of atopic dermatitis increased from 0.028 per person-year in 2009 to 0.034 per person-year in 2014, and for children younger than 1 year, the incidence rate increased from 0.052 per person-year in 2009 to 0.073 per person-year in 2014. Meaning This nationwide study suggests an increase in the incidence rate of pediatric atopic dermatitis, especially among children younger than 1 year.

Introduction:The literature on treatment patterns for paediatric atopic dermatitis (AD) is scarce and is rarely based on real-world data. Using national registers, we sought to establish up-to-date, population-based prevalence estimates, predictors of risk and disease burden and a comprehensive overview of treatment patterns and course for paediatric patients with AD. Methods: Dispensed prescriptions for the entire Norwegian child population aged 0-10 years from 2014 to 2020 were analysed. Results: There were 176,458 paediatric patients with AD. Of these, 99.2% received topical corticosteroids, 5.1% received topical calcineurin inhibitors, 37.1% received potent topical corticosteroids and 2.1% received systemic corticosteroids. Of the 59,335 live births in Norway (2014), 14,385 [24.8%; 95% confidence interval (CI) 24.5-25.1] paediatric patients were treated

Although isotretinoin has anti-inflammatory and immunomodulatory properties, it can exacerbate atopic dermatitis. National estimates of the extent to which patients with atopic dermatitis are affected by severe acne and isotretinoin tolerability are lacking. The aim of this study is to investigate isotretinoin therapy in patients with atopic dermatitis and to compare the nationwide prevalence with individuals without atopic dermatitis. All Norwegian residents were followed for 17 years until age 20–22 years in 2020. Approximately 28% of patients with atopic dermatitis had been treated for acne, and 8% had received isotretinoin before age 23 years. In those over 17 years old, significantly more patients with atopic dermatitis were treated with isotretinoin than those without. At age 22 years, 2.21% (95% confidence interval 1.92–2.49) of patients with atopic dermatitis were treated with isotretinoin, compared with 1.55% (95% confidence interval 1.44–1.65) of those without, representing 42.8% (1.43; 95% confidence interval 1.24–1.65) higher use in patients with atopic dermatitis. Patients who received long-term treatment (probable severe atopic dermatitis) tolerated isotretinoin similarly to patients who received short-term treatment (probable mild atopic dermatitis). There was significantly higher use of topical corticosteroids during isotretinoin therapy in patients with atopic dermatitis. Conclusively, severe acne (isotretinoin therapy) was associated with atopic dermatitis at the population level in young adults.