Systematic Review and Meta-analysis on Synthetic Antifungal versus Keratolytic Agents for Topical Treatment of Pityriasis Versicolor

Abstract

Background. Pityriasis versicolor is a common fungal infection of the superficial skin layer caused by Malassezia furfur, a normal commensal in the skin. Keratolytic agents are popular, cheap, and readily available over-the-counter treatments for pityriasis versicolor. Conventional antifungal agents are more expensive, requiring prescription, and may induce resistant strains. However, evidence of their comparative safety and efficacy is still lacking. Objectives. To assess the efficacy and safety of synthetic antifungals compared to keratolytic agents in the topical treatment of pityriasis versicolor through a systematic review. Methods. We searched the following databases: MEDLINE (from 1966) through PubMed, CENTRAL (Issue 9 of 12, September 2021), EMBASE (from 1974), LILACS (from 1987); Herdin (from 1970), www.clinicaltrials.gov, www.isrctn. com, www.trialregister.nl. We contacted researchers in the field, hand searched relevant conference abstracts, and the Journal of the Philippine Dermatological Society 1992-2019. We included all randomized controlled trials involving patients with diagnosed active pityriasis versicolor where topical antifungal was compared with a topical keratolytic for treatment. Two review authors independently applied eligibility criteria, assessed risk of bias using the Cochrane collaboration tool, and extracted data from included studies. We used RevMan 5.3 to pool dichotomous outcomes using risk ratios (RR) and continuous outcomes using the mean difference (MD), using random-effects meta-analysis. We tested for statistical heterogeneity using both the Chi2 test and the I2 test. We presented results using forest plots with 95% confidence intervals. We planned to create a funnel plot to determine publication bias but were unable to due to few studies. A Summary of Findings table was created using GRADE profile software for the primary outcomes. Results. We included 8 RCTs with a total of 617 participants that compared azole preparations (ketoconazole, bifonazole and econazole) versus keratolytic agents (selenium sulfide, adapalene, salicylic-benzoic acid). Pooled data showed that azoles did not significantly differ from keratolytic agents for clinical cure (RR 0.99, 0.88, 1.12; 4 RCTs, N=274, I2=55%; very low-quality evidence), and adverse events (0.59 [0.17, 2.06]; very low-quality evidence) based on 6 RCTs (N=536). There were two patients given a keratolytic agent (selenium sulfide shampoo) who had acute dermatitis and discontinued treatment. Conclusion. It is uncertain whether topical azoles are as effective as keratolytic agents in clinical clearance and occurrence of adverse events in patients with pityriasis versicolor. A wider search of grey literature and local studies are warranted. Larger RCTs with low risk of bias are recommended.