Epidemiology and clinical features of pustular psoriasis: A 15‐year retrospective cohort

Pustular psoriasis (PuP) is a rare variant of psoriasis with a unique immunopathogenesis, unlike its more prevalent plaque-type counterpart. However, data available are limited due to its low prevalence. This study aimed to describe the demographic profile, precipitating factors, clinical presentations, and treatments among patients with different PuP subtypes from a 15-year retrospective cohort study in Thailand. A total of 60 patients were included in this study. There was female predominance (73.3%) and mean age of onset was 38.1 ± 17.6 years. Generalized PuP (GPP) was the most prevalent subtype (80.0%), followed by acrodermatitis continua of Hallopeau (13.3%) and palmoplantar pustulosis (6.7%). Precipitating factors included corticosteroid withdrawal, upper respiratory tract infection, and pregnancy. One-third of PuP occurred concomitantly with other psoriasis variants, especially the plaque type. The most prescribed systemic and topical treatments were oral acitretin (60.0%) and topical corticosteroids (98.3%), respectively. Only two patients were treated with narrow-band ultraviolet B. In conclusion, four out of every five PuP patients in this center had GPP. Corticosteroid withdrawal, upper respiratory tract infection, and pregnancy are important precipitating factors. Coexistence with other psoriasis variants was identified in one out of every three patients. Acitretin remains the mainstay of systemic treatment.