A Study of Long-term Effect of Dupilumab on Skin Barrier Function in Pediatric Participants With Atopic Dermatitis

This is a 2-year, open-label, exploratory study with a 4-week screening period and a 104-week treatment phase designed to investigate dupilumab's long-term effect on skin barrier function as measured by transepidermal water loss (TEWL) before and after skin tape stripping (STS) in approximately 48 pediatric participants (aged ≥6 and \<15 years at study entry) with moderate-to-severe AD. All eligible participants with AD will be treated with Dupixent® for 104 weeks according to locally approved Dupixent® product label (in country/region where the study is conducted). After the 104-week treatment phase and the last assessment at the End of Treatment (EoT), participants will be followed-up for 4 weeks and an End-of-Study (EoS) visit by telephone at 4 weeks after the EoT visit will end the study for each participant. The maximum duration of the study per participant will be 112 weeks (including screening period). The study population will include approximately 48 pediatric participants with AD for long-term treatment with dupilumab: * Treatment cohort 1 - newly recruited participants with AD (aged ≥6 to \<12 years at study entry) * Treatment cohort 2 - any former PELISTAD participants (from the previous 16-week treatment study \[PELISTAD/LPS16764\] who consent to participate in this long-term study; aged ≥6 to \<15 years at entry to this study)

Study duration for each participant will be approximately 112 weeks, including: * Screening period: Up to 4 weeks (Day -28 to Day -1) from signing the informed consent. * Open-label dupilumab treatment period: 104 weeks (from Day 1/Week 0 to Week 104). * Follow-up period: 4 weeks (safety follow-up phone visit at 4 weeks after the EoT visit).