The Use of Medium-Deep Peelings to Treat Melasma: A Case Series Study

Objective: To evaluate the efficacy and safety of medium-deep chemical peels for melasma in a diverse population using quantitative and subjective methodologies for comprehensive outcome assessment. Methods: A case series of 42 melasma region treatments was conducted from March 2023 to December 2024. Treatments included 30% phenol with 0.8% croton oil or a two-step protocol of 30% glycolic acid followed by 35% trichloroacetic acid (TCA) with 0.7% croton oil. Quantitative pigmentation analysis utilized the weighted skin intensity (WSI) ratio via Fiji ImageJ software. A panel of 20 experts conducted subjective evaluations based on standardized photographs, rating pigmentation reduction, skin tone uniformity, and overall appearance. Statistical analyses included the Wilcoxon signed-rank test and heatmap visualizations. Results: Quantitative analysis showed significant improvements in pigmentation, with mean WSI values increasing from 78.99 ± 19.58 (untreated) to 88.33 ± 22.05 (treated; Z = −5.495), p < 0.001). Heatmaps confirmed uniform pigmentation reductions. Among 42 treatments, 38 showed positive changes (Z = −5.092, p < 0.001). Experts identified 94.4% of cases as post-treatment and rated pigmentation reduction as Grade 4 or 5 in 87.5% of responses, with similarly high ratings for skin tone uniformity (69.4%) and overall appearance (79.4%). Conclusion: Medium-to-deep chemical peels, utilizing phenol-croton oil or TCA, demonstrated significant efficacy in reducing pigmentation, enhancing skin regeneration, and improving overall skin quality. Quantitative analysis and specialized clinical assessments confirmed their role as a targeted and effective approach for melasma treatment. These findings support using medium-to-deep peels as a personalized therapeutic strategy, offering a scientifically validated option for managing refractory melasma.