Characteristics and prevalence of plaque psoriasis in patients with palmoplantar pustulosis.

This large observational study on patients with PPP provides detailed information regarding patient demographics, comorbidities and medication use. The 1-year prevalence of PPP varied in the three studied populations, possibly due to differences in diagnostics and recording practices. Psoriasis frequently co-occurred in patients with PPP. What's already known about this topic? Palmoplantar pustulosis (PPP) is a skin disease of the palms of the hands and soles of the feet and is known to be related to psoriasis. Whether PPP is a distinct disease or a variant of psoriasis is not yet established. The condition is understudied in terms of disease prevalence, disease predictors, patient characteristics and comorbidity. What does this study add? In this study using data from three large population-based cohorts we found low prevalence rates (< 0·1%) of PPP. The prevalence of psoriasis was estimated at between 14·2% and 61·3% in patients with psoriasis. Patients with PPP with co-occurring psoriasis have a higher prevalence of psoriatic arthritis and use of antipsoriatic drugs.