Erythromycin in pityriasis rosea: a double-blind, placebo-controlled clinical trialSharma PK, Yadav TP, Gautam RK, Taneja N, Satyanarayana LJ Am Acad Dermatol. 2000;42:241-244
Sharma et al conducted a trial whose results were remarkable and unexpected. The trial was a double-masked, placebo-controlled trial of erythromycin in the treatment of pityriasis rosea. The patients were children and adults with clinically diagnosed pityriasis rosea. Adult patients were treated with 250 mg of erythromycin 4 times daily and children were treated with 20 to 40 mg/kg daily in 4 divided doses. Controls were given placebo pills or syrup that was identical in appearance. The outcomes of complete, partial, and no clearing of the rash within 2 weeks were assessed by investigators who were unaware of the treatment allocation.
Bigby M. A Remarkable Result of a Double-Masked, Placebo-Controlled Trial of Erythromycin in the Treatment of Pityriasis Rosea. Arch Dermatol. 2000;136(6):775-776. doi:10.1001/archderm.136.6.775