For a study, researchers determined that GPP was a rare condition that had lately benefitted from a standardized definition and clinical coding system. GPP diagnosis had historically been confounded by a lack of illness knowledge, as well as clinical similarities to other kinds of psoriasis. GPP must be distinguished from psoriasis Vulgaris (plaque psoriasis), and greater knowledge of the genetic factors underlying GPP might enhance diagnostic accuracy in the future. GPP appeared at any age, however, it is most frequent during the fifth decade of life. GPP tends to have a female predominance, while incidence varies significantly by geographical location and ethnicity.

GPP had the potential to be fatal, was associated with a number of significant problems, and might need immediate care, particularly for complications caused by systemic inflammation. Understanding the epidemiology of GPP, like that of many uncommon illnesses, was fraught with difficulties. Aside from the limited number of patients, assessing the incidence of uncommon diseases was confounded by research that utilized non-standardized approaches and was done in diverse communities. 

Because of these difficulties in data collection, GPP case estimates varied significantly by geographical location and ethnicity. There was a continuous study into disease features, and insights into regional prevalence estimates were critical to improving the understanding of GPP.

Reference:link.springer.com/article/10.1007/s40257-021-00664-x