Assessment of flare frequency and severity of generalized pustular psoriasis in Japanese patients: A retrospective chart review study

Abstract Background Generalized pustular psoriasis (GPP) is a rare and often refractory disease, and GPP flares can be life threatening. The rarity of GPP prevents the development and evaluation of effective GPP‐specific treatments and obstructs disease understanding. Objectives To evaluate the frequency and severity of GPP flares and the clinical background and treatment history of patients with GPP in Japan. Methods This retrospective, longitudinal, Japanese chart review study included patients diagnosed with GPP (according to Japanese Dermatological Association [JDA] diagnostic criteria), with ≥6 months of continuous observation within 10 years of protocol approval at study sites. Primary outcomes: the frequency and severity of GPP flares during follow‐up. Secondary outcomes: patient characteristics (at time of initial GPP diagnosis) and GPP treatment during follow‐up. Results Overall, 205 Japanese patients were included; 106/205 (51.7%) were male, 146/205 (71.2%) were aged