Cantharidin for the Treatment of Molluscum Contagiosum: A Prospective, Double‐Blinded, Placebo‐Controlled Trial

Abstract

Background/Objective To study the effects and safety of cantharidin in the treatment of molluscum contagiosum. Methods We conducted a prospective, double-blinded, placebo-controlled, randomized clinical trial to evaluate the safety and efficacy of topical cantharidin for treatment of pediatric molluscum contagiosum in an academic ambulatory care center. Twenty-nine children aged 5–10 with the diagnosis of molluscum contagiosum were enrolled to receive treatment with cantharidin or placebo. The main outcome measure was complete clearance of molluscum lesions. Results In contrast to previous retrospective observational studies, the performance of cantharidin treatment over 2 months was not substantially better than the performance of placebo. Limitations The scope of follow-up was limited to 5 visits over 2 months of treatment. In hindsight, we can hypothesize that a longer follow up period may have captured a greater effect of cantharidin. Conclusion We conclude that during a 2 month period, the magnitude of the cantharidin treatment effects in the target population are, at best, not large. This study provided objective unbiased estimates of the magnitude of cantharidin treatment effects and provided important prospective safety data. Our subjects experienced minimal side effects when treated with cantharidin.

Molluscum Contagiosum: Review and Update on Management

“…Although there are many trials, few are RCTs. The largest RCTs support the use of salicylic acid , KOH , imiquimod , cantharidin , curettage , and lemon myrtle oil in the treatment of MC lesions. The studies on PDL treatment appear promising, but larger trials have not been conducted.…”

“…There was no placebo arm for comparison and it is impossible to blind user providers to methods used because the treatments are so noticeably different when being applied. Dosal et al conducted a double‐blind, placebo‐controlled trial and found cantharidin was not beneficial, suggesting that previous study outcomes would have been different if a placebo arm had been added.…”

Safety and efficacy of topical cantharidin for the treatment of pediatric molluscum contagiosum: a prospective, randomized, double‐blind, placebo‐controlled pilot trial

“…Our strategy endorses treatment every 3 weeks. In contrast, prior studies used more frequent (as few as 1–2 weeks between treatments) or less frequent treatments . We postulate that timing may be essential to optimize the efficacy of cantharidin.…”

“…A 2006 prospective trial of various treatments for MC demonstrated a 60% patient/parent satisfaction with cantharidin use; the authors endorsed cantharidin as a rapid, atraumatic option for the office‐based provider . In contrast with these prior studies, in the first reported placebo‐controlled prospective trial, Coloe Dosal et al . suggested that the performance of cantharidin treatment over 2 months was not substantially better than the performance of placebo.…”

Beetle juice: a guide for the use of cantharidin in the treatment of molluscum contagiosum

“…Although considerable retrospective and anecdotal data support cantharidin's efficacy and safety in the treatment of MC (1,3,22,38,40,41), the only RCT that compares cantharidin to placebo did not find a statistically significant difference in the rate of complete clearance at 8 weeks (39). The trial was double blinded but small (n = 29 patients).…”