A study on 15% trichloroacetic acid peel versus diamond-tip microdermabrasion for acanthosis nigricans of neck - Peel or polish?

Objectives: To evaluate and compare the clinical effects of 15% trichloroacetic acid (TCA) peel and diamond-tip microdermabrasion (MDA) in adults with acanthosis nigricans (AN) of the neck. Material and Methods: This prospective, nonrandomized comparative pilot study included 22 adults with clinically diagnosed AN of the neck (11/group). Group A received 15% TCA peel, and Group B underwent diamond tip MDA. Four treatment sessions were performed at 2-week intervals, with final assessment at week 8. AN area and severity index (ANASI), AN scoring chart (ANSC), patient satisfaction, and adverse effects were recorded. Repeated measurements were analyzed using the Friedman test with Holm-adjusted post hoc comparisons; between-group comparisons used the Mann–Whitney U test. Exploratory mixed effects and final visit regression models adjusted for age, disease duration, body mass index (BMI), and baseline score, as applicable. Results: ANASI decreased from a median of 12 (interquartile range 9–19.5) to 6 (4–6) in the TCA group and from 10 (8–19.5) to 6 (4–8) in the MDA group; within-group change was significant in both groups ( p < 0.001). The median absolute reduction was 8 (5.5–10.5) versus 4 (4–10), respectively, but the between-group difference was not significant ( p = 0.354). The adjusted group by visit interaction was not significant for ANASI ( p = 0.443) or ANSC ( p = 0.091). Satisfaction improved over time in both groups, with no significant between-group difference at the final visit ( p = 0.083). Post-inflammatory hyperpigmentation occurred in 2/11 patients receiving TCA and 0/11 receiving MDA ( p = 0.476). Conclusion: Both treatment modalities were associated with improvement over 8 weeks. Although the TCA group showed numerically greater reductions in ANASI and ANSC, the updated unadjusted and adjusted analyses did not demonstrate a statistically significant advantage over MDA. These pilot findings should be interpreted cautiously because of the small, nonrandomized sample and baseline BMI category imbalance.