This study tests if a new medicine, *tralokinumab*, given via subcutaneous (SC) injections, works well and is safe for kids with moderate-to-severe *atopic dermatitis* (AD), a skin condition causing red, itchy skin. This medicine will be combined with topical corticosteroids (TCS), creams used to reduce skin inflammation. The trial includes two age groups: children aged 2 to under 12 years and infants aged 6 months to under 2 years. Kids will receive either tralokinumab or a placebo (a fake treatment) with TCS, while infants only receive tralokinumab with TCS. The trial will last up to 4 years, with visits every 2 weeks for the first year and every 6 weeks afterward. Some visits will be through phone calls.

• The study lasts up to 4 years with frequent check-ups.
• Children may receive a placebo initially, but infants receive the treatment directly.
• Participants need to meet certain health criteria to join the study.

All participants will undergo a screening process to ensure eligibility. After stopping treatment, there is a 4-week follow-up to check on participants' safety. This study aims to improve the quality of life for children with AD.