Proposing Melasma Severity Index: A New, More Practical, Office-based Scoring System for Assessing the Severity of Melasma.

Background: Melasma Area and Severity Index (MASI), the scoring system in melasma, needs to be refined.

Aims And Objectives: To propose a more practical scoring system, named as Melasma Severity Index (MSI), for assessing the disease severity and treatment response in melasma.

Materials And Methods: Four dermatologists were trained to calculate MASI and also the proposed MSI scores. For MSI, the formula used was 0.4 (a × p(2)) l + 0.4 (a × p(2)) r + 0.2 (a × p(2)) n where "a" stands for area, "p" for pigmentation, "l" for left face, "r" for right face, and "n" for nose. On a single day, 30 enrolled patients were randomly examined by each trained dermatologist and their MASI and MSI scores were calculated. Next, each rater re-examined every 6(th) patient for repeat MASI and MSI scoring to assess intra- and inter-rater reliability of MASI and MSI scores. Validity was assessed by comparing the individual scores of each rater with objective data from mexameter and ImageJ software.

Results: Inter-rater reliability, as assessed by intraclass correlation coefficient, was significantly higher for MSI (0.955) as compared to MASI (0.816). Correlation of scores with objective data by Spearman's correlation revealed higher rho values for MSI than for MASI for all raters.

Limitations: Sample population belonged to a single ethnic group.

Conclusions: MSI is simpler and more practical scoring system for melasma.