ABSTRACT Palmoplantar pustulosis (PPP) is an inflammatory skin disease characterized by chronic and relapsing eruptions of multiple sterile pustules on the palms and soles, which subsequently crust and desquamate. In addition to pustules, vesicles and pustulo‐vesicles are often observed simultaneously. It is more prevalent among Japanese individuals, and the number of affected patients in Japan is estimated to be approximately 140,000 based on national health insurance claims data in Japan. Sterile osteitis occurs in 10%–30% of patients with PPP or a history of PPP, a condition referred to as pustulotic arthro‐osteitis. Because it has become evident that focal infections act as triggering factors in approximately 80% of both conditions, their therapeutic algorithms differ fundamentally from those for psoriasis. The aim of the Treatment Guidance for Palmoplantar Pustulosis 2022 was to clarify the clinical manifestations and histopathological findings supporting the diagnosis of PPP, and to explain treatment algorithms and recommendation grades based on differences in triggering factors and pathophysiology between PPP and psoriasis. Although the level of evidence is limited due to the ethical and practical difficulties in conducting rigorous double‐blinde clinical trials to evaluate the efficacy of focal infection treatment, the treatment recommendations were determined through expert consensus based on extensive clinical experience accumulated in Japan, together with relevant basic research findings.
Terui et al. (Sun,) studied this question.