The risk of systemic infections requiring hospitalisation in children with atopic dermatitis: a Danish retrospective nationwide cohort study.
Certain infections can trigger worsening of atopic dermatitis (AD). Further, an increased risk of extra-cutaneous infections has been suggested among children with AD, but data are sparse.To examine whether hospital managed pediatric AD is associated with increased risk of extra-cutaneous infections in childhood requiring hospitalisation.Nationwide based cohort study using Danish registries. All children aged under 18 years with a hospital in- or outpatient diagnosis of AD and reference children without hospital diagnosis of AD were matched on gender and age at first AD diagnosis date (1:10). Children were included from January 1, 1995 to December 31, 2016 and followed up until December 31, 2017. Study outcomes were extra-cutaneous infections that lead to hospitalisation. The severity of AD was defined by dispensations of AD treatments.Of 19,415 AD children (median follow-up 7.4, interquartile range (IQR) 3.3-13.3 years) and 194,150 non-AD children (median follow-up 7.7, IQR 3.6-13.5 years), 56% were boys and 50% aged under 2 years. In adjusted analyses, children with AD had increased occurence of lower respiratory (aHR (adjusted hazard ratio)=1.79, 95% confidence interval (CI95%) 1.65-1.94), upper respiratory (aHR=1.59, CI95% 1.34-1.88), urinary tract (aHR=1.34 CI95% 1.16-1.54), musculoskeletal (aHR=1.33 CI95% CI95% 1.06-1.66), and gastrointestinal infections (aHR=1.24, CI95% 1.14-1.35), compared with children without a hospital diagnosis of AD. The associations did not clearly vary with the AD severity. The absolute risk difference per 10,000 person-years was 26.4 (CI95% 23.0-29.8) for lower respiratory, 3.1 (CI95% 1.6-4.7) for upper respiratory, 3.6 (CI95% 1.8-5.4) for urinary tract, 0.9 (CI95% 0.2-2.0) for musculoskeletal and 8.7 (CI95% 5.7-11.7) for gastrointestinal infections.Children with hospital-managed AD have an increased risk of systemic infections that lead to hospitalization. The absolute risk was generally low.