Acyclovir is not effective in pityriasis rosea: Results of a randomized, triple-blind, placebo-controlled trial.

ABSTRACT

Background: Acyclovir is considered to be an effective treatment for pityriasis rosea but randomized, blinded, placebo-controlled trials have not been performed. Aims: To test the efficacy of acyclovir in pityriasis rosea in a randomized, triple–blind, placebo-controlled trial. Methods: Twenty seven patients with pityriasis rosea were randomly allocated to receive placebo (n = 13) or acyclovir (800 mg fi ve times daily for one week) (n = 14). The severity of disease was assessed by the pityriasis rosea area and severity index. Cure was defi ned as the absence of erythema, with no or minimal scaling. Results: The number of days (mean ± standard deviation) taken for cure was not signifi cantly different between the two groups (placebo 26.54 ± 9.14 days versus acyclovir 33.29 ± 9.49 days; P = 0.0720, t-test; 95% confi dence interval of difference −0.65 to 14.14 days). Limitations: The sample size for the present study was calculated using data from an earlier study. As the standard deviation was not mentioned in that article, a common standard deviation of fi fteen days was assumed. A study with a larger sample size may be more effective in detecting minor treatment differences between acyclovir and placebo, if they exist at all. Conclusion: Acyclovir is not an effective treatment for pityriasis rosea.