Clinical phenotypes of 504 patients with pustular psoriasis from Europe and Egypt: a multicentre observational study

Pustular psoriasis (PP) comprises a group of rare autoinflammatory skin diseases characterized by sterile pustules. Previous studies have focused on cohorts in East Asia and the West, while North African populations have been underrepresented.

To describe the demographic and clinical features of a large cohort of European and Egyptian patients with PP.

We collected data on 504 patients with PP from 13 centres across Egypt and 5 European countries (Estonia, Germany, Spain, Switzerland and the UK); we then analysed their demographic profiles, clinical presentations and treatment histories.

Of 504 patients with PP (424 Europeans and 80 Egyptians), 78 (15.5%) had generalized pustular psoriasis (GPP), 374 (74.2%) had palmoplantar pustulosis (PPP), 12 (2.4%) had acrodermatitis continua of Hallopeau (ACH) and 40 (7.9%) had other or overlapping PP subtypes. PPP was more prevalent among Europeans than among Egyptians (83% vs. 28%), whereas GPP was more prevalent among Egyptians than among Europeans (60% vs. 7%). Europeans included more women than men (80% vs. 40% with GPP, and 79% vs. 23% with PPP; both P < 0.001). The mean age (SD) of European patients was significantly higher than that of Egyptian patients [59.9 (16.8) vs. 36.1 (18.6) years with GPP and 62.2 (16.4) vs. 40.2 (13.8) years with PPP; both P < 0.001]. European patients with GPP had higher rates of psoriasis vulgaris (PV) than Egyptian patients with GPP (29% vs. 10%; P = 0.043). Treatment patterns varied, with ciclosporin being frequently used in Europe, while treatment with methotrexate and steroids was more common in Egypt.

This study highlights significant variations between European and Egyptian patients with PP. European patients more commonly presented with PPP, whereas Egyptian patients had a higher incidence of GPP and fewer diagnoses of comorbid PV.