Clinical trial of topical erythromycin in inflammatory acne

Sixty-nine informed subjects participated in a split-face, double-blind trial of topical erythromycin base 2% in Vehicle/N versus Vehicle/N alone. All subjects had grades II or III acne as described by Pillsbury. Study solutions were assigned to a randomly selected side of the subject's face. Solutions were applied twice daily. Inflammatory lesion counts were performed by the same investigator during the eight weeks of study at biweekly intervals. The difference in inflammatory lesion counts from beginning to end of study for each side of the face was compared utilizing Student's paired t-test. There was not a statistically significant difference in mean inflammatory lesions at the end of eight weeks (D = 1.46, t = 1.36, df 68). There was, however, a significant difference at two and six weeks (D = 2.59, t = 3.72, df 68; D = 1.41, t = 2.03, df 68). Observed differences in lesion counts were not considered to be clinically significant.