Atopic dermatitis (AD) is an inflammatory, multifactorial skin disease characterized by eczematous skin lesions, severe itching, and serious limitations in quality of life. Since 2016, TREATgermany has been a national clinical registry for patients with moderate to severe AD with around 2,550 participating patients, enabling the collection of physical, patient-reported social and psychological data as well as the collection of biosamples in routine care. TREATgermany is one of the largest academically managed AD registries in the world. This current review summarizes a selection of published analyses from registry data from TREATgermany, which retrospectively identified important correlations with regard to treatment response and safety, and investigated quality of life, performance, and mental health under everyday conditions. In addition, initial molecular signatures were identified from the blood and skin samples obtained from the patients included in the registry, which may be useful as prognostic markers.