Erythromycin in pityriasis rosea: A double-blind, placebo-controlled clinical trial.

BACKGROUND The study stemmed from an incidental observation of improvement in 2 patients with pityriasis rosea while receiving erythromycin. OBJECTIVE The purpose of the study was to evaluate the efficacy of erythromycin in patients with pityriasis rosea. METHODS A double-blind, placebo-controlled clinical study was performed in an outpatient setting in a major hospital. Ninety patients over a period of 2 years were alternatively assigned to treatment group or placebo group. Patients in the treatment group received erythromycin in divided doses for 14 days. The response was categorized as complete response, partial response, or no response. All patients were followed up for 6 weeks. RESULTS Both groups were comparable with regard to age at presentation, sex, and average duration of disease at the time of reporting to the clinic. Upper respiratory tract infection before the appearance of skin lesions was reported in 68.8% of all patients. Complete response was observed in 33 patients (73.33%) in the treatment group and none in the placebo group (P <.0001). CONCLUSION Oral erythromycin was effective in treating patients with pityriasis rosea.