Abstract
BACKGROUND: Acanthosis nigricans (AN) features thick, hyperpigmented skin in flexural areas, often indicating insulin resistance. Dermoscopy of AN demonstrates sulci cutis and crista cutis, and differentiates it from other pigmentary dermatoses. Comparative efficacy studies are lacking in the literature. This study evaluates the clinical and dermoscopic changes in AN treated with metformin and pioglitazone. PATIENTS AND METHODS: A randomised open-label trial was conducted on consenting AN patients aged 18 years or older. Patients were randomized to receive either metformin 500mg twice a day or pioglitazone 7.5mg twice a day for 3 months. Clinical grading, anthropometric measurements, and dermoscopic features were compared at baseline and at study completion at 12 weeks using IBM SPSS v26. RESULTS: Sixty-five patients (mean age 35 years) were distributed between two groups. Both drugs significantly improved clinical grading from baseline to 12 weeks. Metformin notably reduced the body mass index (29.55 ± 3.51 kg/m 2 to 28.92 ± 3.44 kg/m 2 ) and weight (76.58 ± 10.21 kg to 74.64 ± 10.30 kg) more than pioglitazone, but there were no significant differences in other parameters. Both drugs significantly changed dermoscopic parameters, including sulci cutis and hyperpigmented dots and globules, with no differences between them. Papillary projection morphology correlated significantly with clinical grading. LIMITATIONS: The limitations of this study include a relatively short study duration, and a lack of assessment of the effect of patient and disease-related factors on treatment response. CONCLUSION: Metformin and pioglitazone both significantly improved AN clinically and dermoscopically, with no significant differences in efficacy between them. Metformin is more effective in reducing weight and body mass index, and is suitable for overweight patients. Pioglitazone is an alternative for those intolerant or unresponsive to metformin. Dermoscopic parameters can indicate early treatment response before visible clinical improvement.