Epidemiological survey of patients with pustular psoriasis in the Japanese Society for Psoriasis Research from 2017 to 2020

The Japanese Society for Psoriasis Research (JSPR) has been conducting annual epidemiological surveys of patients with pustular psoriasis in Japan since 2017. This study aimed to conduct a recent epidemiological analysis of patients with pustular psoriasis who were enrolled in the JSPR from 2017 to 2020. A total of 291 patients from 131 medical institutions were enrolled, of which 47.4% (138 cases) were males and 52.6% (153 cases) were females. The mean ± standard deviation (SD) age of the patients was 57.4 ± 20.3 years (males, 61.2 ± 17.3 years; females, 54.1 ± 22.1 years). The mean ± SD age of the patients at disease onset was 48.5 ± 22.5 years (males, 50.8 ± 20.6 years; females, 46.4 ± 24.0 years). The types of pustular psoriasis observed included the von Zumbusch type (59.8%), annular pustular psoriasis (8.2%), impetigo herpetiformis (6.5%), and acrodermatitis continua of Hallopeau (4.8%), of which, the majority of the patients with impetigo herpetiformis were female. Among the patients, 58.4% were treated with oral medications and 44.0% were treated with biologics. The most common oral medication prescribed was etretinate (52.4%), followed by corticosteroids (24.7%) and cyclosporin (22.9%). The most common biologics used were IL‐17 inhibitors (ixekizumab [28.1%] and secukinumab [22.7%]), followed by tumor necrosis factor (TNF) inhibitors (infliximab [15.6%]) and IL‐23 inhibitors (guselkumab [14.8%] and risankizumab [10.2%]). This survey thus provides new and significant information regarding the recent perspective of pustular psoriasis, such as patient characteristics and treatment trends, in Japan.