How frequently does palmoplantar psoriasis affect the palms and/or soles? A systematic review and meta-analysis

INTRODUCTION: Palmoplantar psoriasis (PPP) is a variant of psoriasis that affects the palms and/or soles. Although PPP is a disabling and therapeutically challenging condition, its epidemiology is poorly defined. AIM: To assess the prevalence of PPP locations (palms, soles or both), and to analyse epidemiological and clinical characteristics of the disease. MATERIAL AND METHODS: Two bibliographic databases (MEDLINE and SCOPUS) were used as data sources searched from inception to October 2017. The selection of articles was limited to human subjects and English or French languages. RESULTS: A search resulted in a total of 293 articles, out of which 24 were utilized for the current systematic review and 21 for meta-analysis. All listed studies comprised a total of 2083 patients with PPP, with more males than females. According to the results of meta-analysis, majority of patients had the highest prevalence of both palms and soles involvement (95% CI: 47–67), with an almost equal prevalence showing palmar (21%; 95% CI: 13–30) or plantar (20%; 95% CI: 12–29) involvement. The most prevalent type of PPP was plaque/hyperkeratotic, followed by the pustular type. CONCLUSIONS: Almost three-fifths (59%) of all PPP patients had involvement of both palms and soles, while exclusive palmar or plantar involvement was seen in 21% and 20% of patients, respectively. Future research should be performed to elucidate basic epidemiological and clinical characteristics of PPP, which would be helpful for proper consideration of this condition.