Atopic dermatitis (AD) is a skin condition that may cause a rash and itching due to inflammation of the skin. Upadacitinib is an approved drug for treating AD. Approximately 1000 adolescents and adult participants who are prescribed upadacitinib by their physician in accordance with local label will be enrolled in up to 40 sites in China. Participants will receive oral upadacitinib tablets as prescribed by their physician according to their routine clinical practice and local label. Participants will be followed up for approximately 12 months. There is expected to be no additional burden for participants in this trial. Participants will attend regular visits during the study at a hospital or clinic according to their routine clinical practice.