Cochrane Review: Interventions for cutaneous molluscum contagiosum

Background Molluscum contagiosum is a common skin infection, caused by a pox virus. The infection will usually resolve within months in people with a normal immune system. Many treatments have been used for molluscum contagiosum but a clear evidence base supporting them is lacking. This is an updated version of the original Cochrane Review published in Issue 2, 2006. Objectives To assess the effects of management strategies (including waiting for natural resolution) for cutaneous, non-genital molluscum contagiosum in otherwise healthy people. Search strategy In June 2009 we updated our searches of the Cochrane Skin Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (Issue 2, 2009), MEDLINE, EMBASE, and LILACS. We also searched ongoing trials registers, reference lists, and contacted pharmaceutical companies and experts in the field. Selection criteria We investigated randomised controlled trials (RCTs) for the treatment of molluscum contagiosum. We excluded trials on sexually transmitted molluscum contagiosum and in people with lowered immunity (including those with HIV infection). Data collection and analysis Two authors independently selected studies, assessed methodological quality, and extracted data from selected studies. Main results Eleven studies, with a total number of 495 participants, examined the effects of topical (9 studies), systemic, and homoeopathic interventions (1 study each). Limited evidence was found for the efficacy of sodium nitrite co-applied with salicylic acid compared to salicylic acid alone (risk ratio (RR) 3.50, 95% confidence interval (CI) 1.23 to 9.92); for Australian lemon myrtle oil compared to its vehicle, olive oil (RR 17.88, 95% CI 1.13 to 282.72); and for benzoyl peroxide cream compared to tretinoin (RR 2.20, 95% CI 1.01 to 4.79). No statistically significant differences were found for 10 other comparisons, most of which addressed 2 topical treatments. Study limitations included no blinding (four studies), many dropouts (three studies), and no intention-to-treat analysis; small study sizes may have led to important differences being missed. None of the evaluated treatment options were associated with serious adverse effects. Authors' conclusions No single intervention has been shown to be convincingly effective in the treatment of molluscum contagiosum. The update identified six new studies, most of them reporting on interventions not included in the original version. However, the conclusions of the review did not change. Plain Language Summary There is not enough evidence to show that any particular treatment is effective for treating molluscum infection. Molluscum contagiosum, in healthy people, is a self limiting, relatively harmless viral skin infection. It affects mainly children and adolescents. It occurs worldwide but is much more frequent in certain geographic areas with warm climates. Molluscum contagiosum usually presents as single or multiple pimples filled with fluid. People may seek treatment for social and aesthetic reasons and because of concerns about spreading the disease to others. Treatment is intended to speed up the healing process. Eleven studies with 495 patients were included in this review. This review found that many common treatments for molluscum, such as physical destruction, have not been adequately evaluated. Several of the treatments that we studied are not part of daily practice. Limitations of several of these studies were: small numbers of patients, the investigators were not blinded, and patients who did not complete the study (which were numerous in some studies) were not included in the analysis. None of the evaluated treatment options were associated with serious adverse effects. Since most lesions will resolve within months, molluscum contagiosum can be left to heal naturally unless better evidence for the superiority of other treatment options emerges.