The assessment of acne vulgaris—the Leeds technique

A grading system for following the clinical course of acne was devised in which overall severity of acne is evaluated on a zero to eight scale anchored to photographic standards that illustrate grades 0, 2, 4, 6, and 8. Experience with use of this system in large-scale clinical trials has shown it to be useful and reliable. Photographs taken at each visit create a permanent and regradable record of each subject's clinical status throughout the course of treatment.