*Adapted with permission from A. Chiang, F. Hafeez and H.I. Maibach, Skin lesion metrics: Role of photography in acne, J Dermatological Treatment, Epub ahead of print, DOI: 10.3109/09546634.2013.813010 (Jul 1, 2013)
To optimally treat acne, an accurate severity assessment is required and while visual assessments have relied on text descriptions, lesion counting and photographic methods, an ideal grading system would be more accurate and reproducible. Further, its ease of use, and time and monetary costs are also important. Here, the authors consider different approaches for improved acne assessments using photography.
Decades ago, Cook et al. proposed an innovative acne grading method—the first photographic standard. Since the size and redness of lesions are not considered by enumeration, lesion counting is not as simple as it seems, and variance can be great. Therefore, to develop a precise, user-friendly and inter-grader consistent system that is capable of documentation for retrospective verification, Cook proposed an overall acne severity scale of 0–8, with reference photos and text descriptions illustrating grades 0, 2, 4, 6 and 8. Both sides of the face were simultaneously photographed by positioning the face parallel to a front-surface mirror, and a set of five reference photographs that elicited the most consistent 2–4–6 response by trained graders and panelists was selected.
This grading scheme was then used in a trial involving three treatment groups having: placebo capsules and topical placebo, oral tetracycline and topical placebo, or topical tetracycline and placebo capsules. The greatest correlation found between two judges, who assessed overall severity grades one week prior to treatment and eight weeks after treatment, were 0.785 and 0.891, respectively. Other trials confirmed that grading overall severity provided a measurement of efficacy that was more consistent between graders and more sensitive to differences between treatments than lesion counts.