An Observational Study to Assess Real-World Use of Upadacitinib Tablets in Adolescent and Adult Participants With Moderate to Severe Atopic Dermatitis in China

Inclusion Criteria: * Adolescents (body weight \>= 40 kg at the Baseline Visit for patients between \>= 12 and \< 18 years of age) and adults at the time of enrollment. * Clinical diagnosis of moderate to severe atopic dermatitis at the time of enrollment. * UPA treatment is indicated for AD and prescribed as per Chinese label / SmPC. * The decision to prescribe UPA is made prior to and independent of study participation. * The participant should not be treated with UPA prior to this study. * Participants who are willing and able to participate in the collection of patient-reported data, including ePROs and eDiary via apps. * The participant (legal representative for adolescents) voluntarily signed an informed consent before any study-related activities are conducted. Exclusion Criteria: * The participant is currently participating in interventional research (not including noninterventional study, observational study, or registry participation). * Any circumstances that the investigator believes may limit the patient's participation and compliance with study procedures.