Association of acanthosis nigricans with insulin resistance in patients with polycystic ovary syndrome.

This study was designed to explore the association of insulin resistance and acanthosis nigricans (AN) in patients with polycystic ovary syndrome (PCOS). Fifty women, 18-37 years old, were included in the study, and divided into five groups consisting of: (I) 10 women with PCOS, abnormal body mass index (BMI) and AN; (II) 10 women with PCOS and abnormal BMI, but without AN; (III) 10 women with PCOS, normal BMI, and no AN; (IV) 10 women with abnormal BMI, but without PCOS or AN; and (V) 10 healthy women with normal BMI. Measurement of fasting glucose and insulin levels before and after oral glucose challenge was performed. Fasting serum insulin levels were found to be significantly lower in groups III, IV and V than in groups I and II, with no significant difference between groups I and II, or between groups III, IV and V. Total insulin response following administration of glucose did not differ significantly between the groups. These findings support the view that obese PCOS patients with AN do not have significantly higher insulin resistance than obese patients without AN. Insulin resistance is a necessary, but not the only, factor leading to the development of AN in patients with PCOS. Other factors should also be considered in the pathogenesis of this cutaneous reaction.