Use of high-dose acyclovir in pityriasis rosea.

BACKGROUND: The association of human herpesvirus 6 (HHV-6) and HHV-7 with pityriasis rosea suggests that systemic drugs directed against HHV may hasten recovery of patients with pityriasis rosea.

OBJECTIVE: The purpose of this study was to verify the efficacy of oral acyclovir in the treatment of pityriasis rosea.

METHODS: Eighty-seven consecutive patients were treated for 1 week with either oral acyclovir (800 mg 5 times daily) or placebo. In all patients, the time of lesion clearing and the number of new lesions appearing during treatment were recorded.

RESULTS: On the 14th day of treatment, 79% of treated patients fully regressed compared with 4% of the placebo group. The lesions cleared in 18.5 days in treated patients and in 37.9 days in the placebo group. Clearance was achieved in 17.2 days in patients treated in the first week from onset and in 19.7 days in the patients treated later. On the 7th day, there were significantly fewer new lesions in patients treated in the first week than in those treated later.

LIMITATIONS: This trial was neither randomized nor double blind. Objectivity was achieved by counting the lesions.

CONCLUSION: Acyclovir may be effective in the treatment of pityriasis rosea, especially in patients treated in the first week from onset, when replicative viral activity of HHV is probably very high.