Longitudinal atopic dermatitis control and persistence vary with timing of disease onset in children: A cohort study.

BACKGROUND: Wide variation exists in the timing of atopic dermatitis (AD) disease onset among children. Distinct trajectories of early-onset, mid-onset, and late-onset AD have been previously described. OBJECTIVE: To evaluate longitudinal disease control and persistence with respect to age at onset of AD. METHODS: A cohort study was performed using the Pediatric Eczema Elective Registry, a prospective observational cohort of subjects with childhood-onset AD. AD control and persistence were assessed biannually for up to 10 years. RESULTS: A total of 8015 subjects with 41,934 person-years of follow-up were included. In longitudinal analyses using generalized linear latent and mixed modeling, older age at onset of AD was associated with better disease control and less-persistent AD. For each additional year of age at onset of AD, the adjusted odds ratios for poorer AD control and for persistent AD were 0.93 (95% confidence interval, 0.91-0.94) and 0.84 (95% confidence interval, 0.80-0.88), respectively. Differences in AD control and persistence among subjects with early-, mid-, and late-onset AD were most pronounced from early adolescence onward. LIMITATIONS: Misclassification bias may arise from using self-reported data on age at onset. Attrition and missing data in longitudinal studies may introduce bias. CONCLUSION: Early-, mid-, and late-onset pediatric AD appear to be clinically distinct subtypes of the disease.