Azithromycin does not cure pityriasis rosea

OBJECTIVES. Pityriasis rosea (PR) is a common skin disorder in children. Its cause is unknown. A recent publication reported a 73% cure rate in patients with PR after treatment with erythromycin. To duplicate this result using a drug with fewer adverse effects and greater biological half-life, we set out to study the effect of azithromycin on PR. Azithromycin is an azalide antibiotic with a spectrum of antimicrobial activity very similar to that of erythromycin. DESIGN. We randomly assigned 49 children with PR to receive either azithromycin (12 mg/kg per day, up to a maximum of 500 mg/day) for 5 days or a similar-appearing placebo. Study physicians were blinded to patients' treatment type. Two pediatricians had to agree on the diagnosis of PR before patients could be enrolled. Subjects were seen at follow-up visits 1, 2, and 4 weeks after starting treatment. OUTCOME MEASURES. We measured the appearance of new lesions and resolution of lesions. RESULTS. Rates of cure and of partial resolution were similar in the azithromycin and placebo groups. CONCLUSION. Azithromycin does not cure PR.