A Case Series: Experience of Using 20% Potassium Hydroxide Solution to Treat Adult Sexually Transmitted Molluscum Contagiosum

Background: Molluscum contagiosum (MC) is a benign disease of the skin and mucous membrane caused by a poxvirus. To date, there is no standard therapy used for the treatment of MC. Using 10% of potassium hydroxide (KOH) once or twice a day and 20% KOH once a day are often applicable to MC lesions both in children and adults. Nevertheless, the usage of 20% KOH twice a day still has not been reported.

Purpose: This case series aimed to show the efficacy and side effects of once- or twice-daily application of 20% KOH solution for MC lesions due to sexually transmitted infections (STIs) in adults.

Patients and methods: Three cases of MC on the genital were applied once or twice daily and one case of MC on the face was applied twice daily using 20% KOH solution.

Results: As a result, the application of 20% KOH twice daily showed the improvement of MC lesions on the face on day 7 and MC lesions on the genital on day 20. Meanwhile, once-daily application of 20% KOH showed diminished MC lesions on genital on day 25-31 after treatment. There were tolerable side effects that occurred in this treatment, such as stinging and burning sensation several minutes after application, erosions, and post-inflammatory hypo- and hyper-pigmentation.

Conclusion: The 20% KOH solution twice daily on MC lesions in adults is effective, practical, and inexpensive.