Tools for Practice


#232 Muscling out molluscum contagiosum: Which treatments work?


CLINICAL QUESTION
How effective are commonly used therapies for molluscum contagiosum? 


BOTTOM LINE
If treated, molluscum contagiosum will have complete clearance of lesions within 3 months for ~15% given placebo, ~30% given cantharidin 0.7%, and 50-80% given potassium hydroxide 10-15%, cryotherapy or perhaps curettage (very limited evidence). Imiquimod is not effective.  



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EVIDENCE
One systematic review1 and three recent randomized controlled trials2-4 (RCTs) evaluated complete resolution of lesions in immunocompetent pediatric patients within 3 months of starting treatment: 
  • Potassium hydroxide 10-15% once or twice daily: 
    • Versus placebo (3 RCTs, 163 patients; meta-analyzed by PEER):1,3,4 49% versus 17% placebo, Number Needed to Treat (NNT)=4. 
    • Versus curettage (1 RCT, 34 patients):1 81% versus 88% curettage, not statistically different.  
    • Versus cryotherapy once/week for 4-6 weeks (2 RCTs, 150 patients, 1 RCT including children and adults; meta-analyzed by PEER):1,4 81% versus 85% cryotherapy, not statistically different. 
  • Cantharidin 0.7% solution applied 2-5 times over 6-8 weeks: 
    • Versus placebo (2 RCTs, 123 patients; meta-analyzed by PEER):1,2 32% versus 10% placebo, NNT=5. 
  • Imiquimod 5% 3-7 times/week: 
    • Versus placebo (4 RCTs, 850 patients): 15% versus 12% placebo, not statistically different.1 
    • Versus potassium hydroxide 10% (2 RCTs, 67 patients):1 53% versus 82% potassium hydroxide, number needed to harm (NNH)=4.  
    • Versus cryotherapy once/week (1 RCT, 74 patients):1 59% versus 100% cryotherapy, NNH=3. 
  • Adverse Events: 
    • Site reaction: imiquimod versus placebo (3 RCTs, 827 patients): 36% versus 26% placebo, NNH=11.1 
    • Burning sensation: 1 RCT 53% potassium hydroxide versus 12% placebo, NNH=3 (pain/stinging not statistically different).3 
Context: 
  • Limitations: Patients did not have or were not treated for genital lesions. 
  • Potassium hydroxide may cause chemical burns with improper use; should be applied sparingly, directly to lesion. When redness appears, discontinue use and wait for lesion to heal.5 
  • Estimated incidence of molloscum contagiosum is 12-14 cases per 1000 children per year.6 
  • Molluscum contagiosum is benign; the majority of cases resolve within a year without treatment.7 
    • In some cases, treatment may be preferable to improve quality of life and limit the risk of transmission.8 
  • Cryotherapy, cantharidin and curettage require in-office treatment. 


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Author(s):

  • Danielle Perry BScN RN
  • G. Michael Allan MD CCFP
  • Nicolas Dugré PharmD MSc

1. Van der Wouden JC, van der Sande R, Kruithof EF, et al. Cochrane Database Syst Rev. 2017; 5:CD004767

2. Guzman A, Schairer D, Garelik J, et al. Int J Dermatol. 2018 ;57(8):1001-6.

3. Teixidó C, Díez O, Marsal JR, et al. Pediatr Dermatol. 2018; 35(3):336-42.

4. Giner-Soriano M, Teixidó C, Marsal J, et al. J Dermatolog Treat. 2019:1-7.

5. ACM Laboratoire Dermatologique. Treatment of molloscum contagiosum. Available at: https://www.labo-acm.com/en/molluscum-contagiosum/58-molutrex.html. Last accessed February 26, 2019.

6. Qureshi A, Zeb M, Jalal-Ud-Din M, et al. J Ayub Med Coll Abbottabad. 2016; 28(2): 382-385.

7. Olsen JR, Gallacher J, Piguet V, et al. Family Practice. 2014;31(2): 130-6.

8. Olsen JR, Gallacher J, Finlay AY, et al. Lancet Infect Dis. 2015;15:190-5.

Authors do not have any conflicts of interest to declare.