Development of a Photographic Scale for Consistency and Guidance in Dermatologic Assessment of Forearm Sun Damage

Abstract

OBJECTIVES: To develop a photographic sun damage assessment scale for forearm skin and test its feasibility and utility for consistent classification of sun damage. DESIGN: For a blinded comparison, 96 standardized 8 × 10 digital photographs of participants' forearms were taken. Photographs were graded by an expert dermatologist using an existing 9-category dermatologic assessment scoring scale until all categories contained photographs representative of each of 4 clinical signs. Triplicate photographs were provided in identical image sets to 5 community dermatologists for blinded rating using the dermatologic assessment scoring scale. SETTING: Academic skin cancer prevention clinic with high-level experience in assessment of sun-damaged skin. PARTICIPANTS: Volunteer sample including participants from screenings, chemoprevention, and/or biomarker studies. MAIN OUTCOME MEASURES: Reproducibility and agreement of grading among dermatologists by Spearman correlation coefficient to assess the correlation of scores given for the same photograph, κ statistics for ordinal data, and variability of scoring among dermatologists, using analysis of variance models with evaluating physician and photographs as main effects and interaction effect variables to account for the difference in scoring among dermatologists. RESULTS: Correlations (73% to >90%) between dermatologists were all statistically significant (P < .001). Scores showed good to substantial agreement but were significantly different (P < .001) for each of 4 clinical signs and the difference varied significantly (P < .001) among photographs. CONCLUSIONS: With good to substantial agreement, we found the development of a photographic forearm sun damage assessment scale highly feasible. In view of significantly different rating scores, a photographic reference for assessment of sun damage is also necessary.