Clinical and genetic differences between pustular psoriasis subtypes

TLDR: In this paper, the authors sought to characterize the clinical and genetic features of pustular psoriasis through the analysis of an extended patient cohort, including 863 unrelated patients (251 with GPP, 560 with PPP, 28 with acrodermatitis continua of Hallopeau [ACH], and 24 with multiple diagnoses).

Abstract: Background The term pustular psoriasis indicates a group of severe skin disorders characterized by eruptions of neutrophil-filled pustules. The disease, which often manifests with concurrent psoriasis vulgaris, can have an acute systemic (generalized pustular psoriasis [GPP]) or chronic localized (palmoplantar pustulosis [PPP] and acrodermatitis continua of Hallopeau [ACH]) presentation. Although mutations have been uncovered in IL36RN and AP1S3, the rarity of the disease has hindered the study of genotype-phenotype correlations. Objective We sought to characterize the clinical and genetic features of pustular psoriasis through the analysis of an extended patient cohort. Methods We ascertained a data set of unprecedented size, including 863 unrelated patients (251 with GPP, 560 with PPP, 28 with ACH, and 24 with multiple diagnoses). We undertook mutation screening in 473 cases. Results Psoriasis vulgaris concurrence was lowest in PPP (15.8% vs 54.4% in GPP and 46.2% in ACH, P  Conclusions The analysis of an unparalleled resource revealed key clinical and genetic differences between patients with PPP and those with GPP.