BACKGROUND: Palmoplantaris pustulosis (PPP) is a chronic relapsing skin condition characterized by sterile pustules on the palm and soles. Population-based estimates of PPP incidence and prevalence are limited.
OBJECTIVES: To estimate the prevalence and incidence of PPP in the Swedish general population and to estimate the prevalence of psoriasis vulgaris among the PPP population.
METHODS: The Swedish National Patient Register, covering all inpatient and outpatient non-primary care for the Swedish population, was used. We identified cases (2004-2015) with one ICD-10 diagnostic code (base case) for PPP. The point prevalence estimates at the end of this period (31 December 2015) were obtained by linkage to the Swedish Total Population Register. In sensitivity analyses, we used alternative case defintions:1) requiring two visits, 2) requiring two visits of which one within dermatology/internal medicine.
RESULTS: The base case prevalence of PPP was estimated to be 147/100 000 (women=227, men=68) and the annual prevalence was estimated to 26/100 000 in 2015. Among the PPP population, 17% were registered with a diagnostic code for psoriasis vulgaris. The incidence of PPP in 2015 was estimated to be 12.7/100 000 (women=18.7, men=6.6). The criteria used had an impact on prevalence and incidence estimates; strict case 1) 72/100 000 and 2) 5.4/100 000.
CONCLUSIONS: Results indicate that the population-based prevalence of PPP may be larger than previous estimated. However, the estimates were sensitive to employed PPP case criteria. The findings enhance demands for studies using validated diagnostic algorithms potentially also including data from the primary care setting.