Picture‐based acne lesion counts: A validation study to assess accuracy and reliability of acne lesion counts via photography.

Background: Acne lesion counting (ALC) is widely used to evaluate efficacy of new acne treatments. Although such evaluations are precise and highly discriminative, if assessed live, it can be a time‐consuming and intrusive measurement. Photographic assessment is a viable mode for ALCs and for training and/or qualifying evaluators. Aims: The purpose of this study was to validate photographic methods for performing ALCs and to provide an objective measurement tool to train and/or qualify lesion count evaluators for deployment in both small‐ and large‐scale studies. Patients/Methods: Assess accuracy and reliability of acne lesion counting via photographic methods in 8 subjects aged 16 to 40 years, with Fitzpatrick Skin Types I to VI. Frontal and 45°angle images taken at the single in‐clinic visit. Each subject underwent 3 counts per 4 evaluators: 1 set of live counts and 2 sets of photo counts. Intra‐evaluator and inter‐evaluator reliability measures for photo counts were evaluated using calculations of intraclass correlation coefficients (ICCs). Results: Eight subjects (2 males and 6 females) age between 16 and 40 (min 16 years, max 25 years) diagnosed with facial acne vulgaris participated in the study. Fitzpatrick Skin Types ranged from III to V (three Type‐III, four Type‐IV, and one Type‐V). ICC values for intra‐evaluator reliability were found to be >0.95 for each evaluator, and ICC for inter‐evaluator reliability was found to be 0.98. Conclusions: Photographic lesion count methodology is a reliable and accurate tool for objective measurement of ALCs and additionally, for training and/or qualifying evaluators. [ABSTRACT FROM AUTHOR]