There are many expert reviews reporting on the treatment of molluscum contagiosum, but very few randomized placebo-controlled trials. To date, no trial has compared watchful waiting with different treatment strategies. Most available trials are small, have poor methodological quality and are not generalizable to primary care. A Cochrane review concluded that, at present, no reliable evidence-based recommendations can be given for the treatment of non-genital molluscum contagiosum in immunocompetent people. Unless robust evidence emerges for effective and safe treatment, clinicians should consider expectant management (e.g. waiting for spontaneous resolution of the molluscum lesions).

• A Cochrane review (search date: March 2004) included five randomized controlled trials (RCTs) including 137 people. Most of the studies identified could not be included because they were uncontrolled case series, which were open to significant bias, and the results were difficult to evaluate due to the high rate of spontaneous resolution of molluscum contagiosum. The studies that met the inclusion criteria were small, had methodological problems and high drop-out rates, and some did not include intention-to-treat analysis. There were no studies examining cryotherapy or needle expression [van der Wouden et al, 2006]:
• One study (n = 30) compared sodium nitrite 5% and salicylic acid 5% under occlusion with salicylic acid 5% alone. A statistically significant higher rate of lesion cure at 3 months was found with sodium nitrite compared with salicylic acid alone. This finding is difficult to interpret as there was no placebo arm.
• Another study (n = 35) found a shorter mean duration to cure in the group treated with iodine plus salicylic acid plaster compared with iodine alone or salicylic acid alone. All participants developed redness of the skin at the treatment site within 3 to 7 days after the start of treatment.
• The other three studies showed no significant difference in complete cure or lesion improvement compared with placebo for topical potassium hydroxide 10% (n = 20), systemic cimetidine, or calcarea carbonica (a homeopathic remedy).
• One study (n = 14, average age 4.6 years) compared physical expression (squeezing) with phenol ablation, but this was non-randomized and lesions were the unit of treatment and analysis [Weller et al, 1999]:
• Cure rates at 1 month were 75% for physical expression and 77% for phenol ablation, which was considered higher than would be expected from natural resolution.
• A total of 63% of lesions treated by physical expression showed no scarring, compared with only 19% of those treated with phenol.
• A prospective randomized trial compared four treatments for molluscum contagiosum in 124 children (1–16 years of age). The treatments included curettage, topical cantharidin 0.7%, topical salicylic acid 16.7% with lactic acid 16.7%, and imiquimod 5% [Hanna et al, 2006]:
• The trial suggested curettage was the optimal treatment based on individual and parental satisfaction, number of visits needed, and adverse effects.
• The results of this study need to be considered with caution, as there was no placebo-control group, treatments were initiated in secondary care, and follow up was carried out over the telephone and relied on parental reporting. All children, in addition, received curettage to other lesions. These methodological limitations, and poor applicability to primary care, limits the usefulness of the findings for primary care in the UK.
• A number of alternative/complementary therapies are advocated for the treatment of molluscum contagiosum, but their effectiveness is unproven.
• In addition to the trial of a homeopathic remedy included in the Cochrane review, we found a small RCT (n = 31 children) assessing an essential oil. Results from this trial suggest that application of essential oil of Australian lemon myrtle might be an effective treatment, but further research is needed [Burke et al, 2004].