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

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).