Clinical Characteristics of Patients with Pustular Psoriasis: A Single-Center Retrospective Observational Study.

Clinical and epidemiologic data on pustular psoriasis are scarce. To investigate the phenotypes of pustular psoriasis and the patients' characteristics observed in a real-life retrospective observational study. The number of incident cases of pustular psoriasis registered in the period 2005-2021 was retrieved from the electronic medical records of the University Hospital of Verona. One hundred and forty cases of pustular psoriasis were collected. Ninety-one out of 140 patients (65%) were females, with a median (IQR) age of 57 (43-66) years. According to the ERASPEN classification criteria, 116 patients (83%) had palmoplantar pustulosis (PPP), 13 (9%) generalized pustular psoriasis (GPP), and 11 (8%) acrodermatitis continua of Hallopeau (ACH). Gender distribution and median age were consistent among the three groups. The prevalence of psoriatic arthritis in GPP, ACH, and PPP was 8%, 36%, and 28%, respectively. During the same period, a total of 4718 cases of plaque psoriasis were retrieved, with a 1:34 ratio of pustular over plaque psoriasis. Pustular psoriasis is much rarer than plaque psoriasis, with PPP being the more common subtype.