Although it is well known that the clinical expression and course of chronic inflammatory skin diseases are highly variable, there are insufficient epidemiological data on this, and the factors that determine the manifestation, clinical features and course are also largely unknown. There are currently no reliable markers that could predict or delineate patient subgroups to support patient management. The aim of this project is to identify clinical and molecular factors that correlate with disease, disease subtypes and progression through in-depth long-term clinical characterization of patients with chronic inflammatory skin diseases and examination of individual biomaterials.

Chronic inflammatory skin diseases such as atopic dermatitis (AD), psoriasis (Pso) and Hidradenitis suppurativa (HS) are very heterogeneous diseases. Onset, clinical features, disease severity, individual trigger factors and response to therapy vary widely between patients and over time, presenting a clinical challenge for diagnosis, counseling, and individualization of management. With the growing interest in inflammatory skin diseases, the need has been recognized to better investigate their natural course and trajectories, associations with environmental and lifestyle factors, and clinical and molecular features underlying their heterogeneity. Initial pilot studies suggested disease subtypes that differ molecularly and/or clinically; however, molecular profiles in particular are subject to variation over time and not necessarily stable. To confirm and extend such preliminary observations, a larger cohort of patients will be studied with careful longitudinal clinical characterization as well as repeatedly obtained specimens, in order to gain deeper insights into disease dynamics. In particular, we will search for clinical and molecular factors that correlate with disease progression and subtypes, and investigate variability in the regulation of molecular mechanisms over time and at resolution and flare-ups.

Inclusion Criteria:

• dermatologist-diagnosed inflammatory skin disease
• informed consent

Exclusion Criteria:

• subject and/or the legal guardians are not able to give written informed consent
• pregnant and breastfeeding women
• concurrent participation in a clinical trial
• use of systemic immunosuppressive therapy or phototherapy during the last 4 weeks or receipt of biologics therapy (e.g. dupilumab, tralokinumab) within the last 3 months
• treatment of the target skin areas with topical corticosteroids, calcineurin inhibitors or emollients 24 hours before sample collection

Patients with chronic inflammatory skin disease Healthy control individuals

IPD can be made available only to individual collaborating researchers in compliance with other researchers in line with national as well as international data protection laws (e.g. GDPR, DSGVO)