Prologue: 2019 Annual Meeting of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA).

The 2019 Annual Meeting of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) was held in Paris, France, and was attended by rheumatologists, dermatologists, representatives of biopharmaceutical companies, and patients. As in previous years, GRAPPA members held a symposium for trainees to discuss their research in psoriatic disease with experts in the field. Other subjects featured during the annual meeting included a composites workshop to review continuous composite measures; the GRAPPA-Collaborative Research Network's third annual meeting; the need for a precision medicine approach to the treatment of psoriatic disease; updates from working groups in International Dermatology Outcome Measures and Outcome Measures in Rheumatology; a debate on the effectiveness of methotrexate in the treatment of psoriatic arthritis (PsA); updating recommendations for optimal treatment approaches for patients with PsA; an update on GRAPPA's research and educational projects; and the GRAPPA ultrasound (US) working group's goal to optimize the evaluation of enthesitis in patients with PsA using US through the development of a diagnostic US enthesitis tool. In this Prologue, we introduce the papers that summarize that meeting.