Interventions for chronic palmoplantar pustulosis: abridged Cochrane systematic review and GRADE assessments

Background Palmoplantar pustulosis (PPP) is a chronic inflammatory disease in which sterile and relapsing pustules appear on the palms and soles. Objectives To assess the effects of interventions for chronic PPP to induce and maintain complete remission. Methods We searched for randomized controlled trials (RCTs), including people with PPP or chronic palmoplantar pustular psoriasis, in the Cochrane Skin Specialised Register, CENTRAL, MEDLINE, Embase, LILACS and eight trials registers up to July 2020. Study selection, data extraction and risk-of-bias assessment were carried out independently by two review authors. Certainty of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) method. Results We included 37 RCTs (1663 participants, 76% women, mean age 50 years). Mean treatment duration was 11 weeks. Topical vitamin D derivative may be more effective than placebo in achieving clearance [risk ratio (RR) 7.83, 95% confidence interval (CI) 1.85-33.12; low-certainty evidence from two trials]. Concerning biological therapies, there was little or no difference between etanercept and placebo in achieving clearance (low-certainty evidence from one trial), ustekinumab is less effective than placebo in reducing severity (low-certainty evidence from one trial), and guselkumab (RR 2.88, 95% CI 1.24-6.69) and secukinumab (RR 1.55, 95% CI 1.02-2.35) are probably better in reducing disease severity (moderate-certainty evidence from two and one trial(s), respectively) but may cause more serious adverse events than placebo. Conclusions Evidence is lacking for or against major chronic PPP treatments. Risk of bias and imprecision limit our confidence in the results.