Long-term disease progression in adult atopic dermatitis: A 6-year observational study of severity and treatment patterns

BACKGROUND: Atopic dermatitis (AD) is a chronic and heterogeneous skin condition, often with a fluctuating and unpredictable disease course, which can be influenced by treatment patterns and significantly impact patients' disease burden and mental health. OBJECTIVE: To characterize disease trajectories stratified by severity and treatment modality, and investigate their association with patient-reported signs, symptoms, and mental health burden. METHODS: Patients (≥18 years) with a dermatologist-verified diagnosis of AD were included using data from the Danish Skin Cohort and the Danish National Prescription Registry. Patients were categorized into four groups based on AD severity (mild vs. moderate-to-severe) and treatment modality (non-systemic vs. systemic). Disease trajectories were initially identified through graphical assessment of the four groups over time, subsequently each patient was assigned to a disease trajectory using the Longest Common Subsequence method resulting in six clusters. RESULTS: From 2018 through 2024, 234 patients were followed prospectively. Severity and treatment data were recorded at five time points. The majority of patients had moderate-to-severe AD throughout the study period without receiving systemic treatment or achieving remission, but the proportion receiving systemic treatment increased from 17.1% in 2018 to 29.1% in 2024 irrespective of disease severity. The three clusters with consistent moderate-to-severe AD showed similar baseline itch, body surface area, and flare frequency despite different treatment modalities. Clusters having mild AD at some time points showed comparable baseline profiles despite their different trajectories. CONCLUSION: A considerable proportion of patients with moderate-to-severe AD were managed without systemic therapies, and experienced substantial burden and mental health impact. These findings highlight the heterogeneity and persistence of AD, including fluctuating disease activity and variability in treatment patterns, which emphasize the importance of incorporating longitudinal disease patterns into clinical decision-making.