Skin hyperpigmentation index in melasma: A complementary method to classic scoring systems

Abstract

BackgroundDue to relapsing nature of melasma with significant impact on quality of life, an objective measurement score is warranted, especially to follow‐up the patients with melasma and their therapy response in a quantitative and precise manner.AimsTo prove concordance of skin hyperpigmentation index (SHI) with well‐established scores in melasma and demonstrate its superiority regarding inter‐rater reliability. Development of SHI mapping for its integration in common scores.MethodsCalculation of SHI and common melasma scores by five dermatologists. Inter‐rater reliability was assessed by intraclass correlation coefficient (ICC) and concordance by Kendall correlation coefficient.ResultsStrong concordance of SHI with melasma area and severity index (MASI)‐Darkness (0.48; 95% CI: 0.32, 0.63), melasma severity index (MSI)‐Pigmentation (0.45; 95% CI: 0.26, 0.61), and melasma severity scale (MSS) (0.6; 95% CI: 0.42, 0.74). Using step function for mapping SHI into pigmentation scores showed an improvement of inter‐rater reliability with a difference in (ICC of 0.22 for MASI‐Darkness and 0.19 for MSI‐Pigmentation), leading to an excellent agreement.ConclusionSkin hyperpigmentation index could be an important additional cost‐and time‐conserving assessment method, to follow‐up the patients with melasma undergoing brightening therapies in clinical studies, as well as in routine clinical practice. It is in strong concordance with well‐established scores but superior regarding inter‐rater reliability.