Objective: To evaluate the literature to determine which oral and topical medications are most effective in the treatment of insulin resistance obesity-related acanthosis nigricans (IRORAN).
Data sources: A MEDLINE literature search was conducted (1950-January 2008) using the search terms acanthosis nigricans (AN), metformin, rosiglitazone, octreotide, retinoic acid, acitretin, etretinate, and isotretinoin. The search was limited to articles on treatment of IRORAN in humans written in the English language. Articles were retrieved and all references were reviewed.
Study selection and data extraction: Articles selected for inclusion were limited to AN related to obesity with no other underlying etiology. Clinical trials and case reports using monotherapy were included.
Data synthesis: Metformin, rosiglitazone, octreotide, vitamin D analogs, and retinoic acid have been used in the treatment of IRORAN. In one randomized trial, metformin 500 mg 3 times daily was compared with rosiglitazone 4 mg once daily. Neither treatment demonstrated significant improvements in AN; however, rosiglitazone did significantly decrease serum insulin levels. In a second clinical trial and in several case reports, AN and hyperinsulinemia did show improvement with metformin treatment. After a 6-month period, octreotide improved IRORAN, body weight, and glucose/insulin response to a meal. The improvements persisted for 6 additional months after discontinuation of octreotide. Vitamin D analogs and retinoids produced inconsistent results in 5 separate case reports.
Conclusions: IRORAN is a growing problem, particularly in children and adolescents, secondary to the increase in the prevalence of obesity. Treatment of IRONAN should focus on reversal of the underlying hyperinsulinemia. Patients with IRORAN may benefit from a trial of metformin for improvement of lesions and underlying hyperinsulinemia.