ActiPso: definition of activity types for psoriatic disease: A novel marker for an advanced disease classification

Background: Assessment of psoriasis is exclusively done measuring severity using somatic scores such as the psoriasis area and severity index or patient-reported outcomes such as the dermatology life quality index. There is no established tool to measure a patient's individual psoriasis activity over time. Objectives: Development of a new tool to classify psoriasis activity types. Methods: Open patient interviews were performed and adapted in several steps and by using different groups of patients. Wording of the tool's axis and description how to use it was optimized with the input of patients. The final ActiPso tool was used in a prospective study in psoriasis patients. Results: Four activity types could be identified describing psoriasis intensity (e.g. severity, itch, pain) over one typical year and an event/trigger type describing flares. In the study in 586 psoriasis patients of the 536 patients eligible for analysis 40.9% self-classified as type 1 (‘stable’), 22.6% as type 2 (‘unstable’), 30.6% as type 3 (‘winter type’) and 6.0% as type 4 (‘summer type’), respectively. Flares of psoriasis as identified by the event/trigger type were reported in 36.1% of patients with activity type 1, 67.8% with type 2, 73.8% of type 3 and 59.4% of type 4, respectively. Conclusions: Interviewed patients were able to describe their course of psoriatic disease and to name potential triggering factors. By doing so, activity types of psoriasis were defined for the first time and the importance of events/triggers for flares described and integrated into ActiPso types as a basis for advanced patient-centric management. A limitation of ActiPso is that in regions with no seasonal variations types 3 and 4 may not apply.