Oral erythromycin is ineffective in the treatment of pityriasis rosea.

BACKGROUND: Despite the availability of various medical treatments for pityriasis rosea, a large percentage of patients fail to achieve satisfactory results. Erythromycin is reported to be effective in the treatment of pityriasis rosea.

METHODS: We designed a placebo-controlled study on 184 patients with pityriasis rosea attending the outpatient dermatology department at Hazrat-e-Rasul Hospital in Tehran, Iran. Adult patients were treated with 200 mg of erythromycin 4 times daily and children were treated with 20 to 40 mg/kg daily in 4 divided doses. Controls were given a placebo (an emollient cream) that was not identical in appearance. Subjects were seen at follow-up visits 2, 4, 6, and 8 weeks after starting treatment.

RESULTS: Both groups were comparable with regard to sex, age, and mean duration of disease at the time of attending the clinic. We found no significant difference between the 2 treatment groups at weeks 4, 6, and 8 after beginning of treatment. (p > .05 Chi2).