The aim of this study was to analyse sick leave in generalized pustular psoriasis, the most severe form of pustular psoriasis. Prolonged sick leave of >14 days was analysed for 502 patients with generalized pustular psoriasis compared with controls with psoriasis vulgaris and matched controls from the general population. Using data from the Swedish National Patient Register, and the Longitudinal integrated database for health insurance and labour market studies, the study estimated the mean number of sick leave days in the year of first diagnosis of generalized pustular psoriasis (index year) and for 2 years before and after the index year. Patients with generalized pustular psoriasis were on sick leave to a larger extent than both control populations for all study years. The number of sick leave days peaked in the index year and then reduced. Compared with the control populations, sick leave in generalized pustular psoriasis was already higher prior to diagnosis, indicating delayed diagnosis and/or a comorbidity burden.