Comparison of Metformin versus Rosiglitazone in Patients with Acanthosis Nigricans: A Pilot Study

Background: Acanthosis nigricans (AN) is a skin condition commonly present on the neck of obese subjects. Obesity is often accompanied by insulin resistance and/or hyperinsulinemia. Metformin and rosiglitazone are 2 pharmacologic agents useful in conditions characterized by insulin resistance. Objective: The aim of our study was to compare the efficacy of metformin versus rosiglitazone on AN lesions of the neck as well as their effects on metabolic and anthropometric variables. Methods: This 12-week randomized, open-label pilot study involved overweight or obese subjects with AN treat with either metformin (n=14) or rosiglitazone (n=13). Results: Only the rosiglitazone group showed a significant reduction in insulin levels. No effect on the severity of AN was observed, but modest improvements of skin texture occurred in both treatment groups. Conclusions: Metformin and rosiglitazone were well-tolerated. Although efficacy on skin lesions was very modest, their use in acanthotic subjects might be useful during longer treatment periods.