Serum Insulin and Insulin Resistance in Patients with Acanthosis Nigricans

Background: Acanthosis nigricans is a common dermatological problem especially in obese patients. Its etiopatogenesis is not well understood, but there are many associated abnormalities that could be seen like hormonal changes in a form of insulin resistance and malignancy. Objective: To evaluate the state of serum insulin and insulin resistance in Iraqi patients with acanthosis nigricans. Patients and Methods: A case-control study was conducted in the Department of Dermatology and Venereology Baghdad Teaching Hospital during the period from April 2005 to July 2006. Thirty patients with acanthosis nigricans were included in this work their ages ranged from 13-40 years with the mean age ±SD of 27.06 ±5.58 years. In addition to 30 healthy control subjects which matched with patients group in age, sex, duration of disease and BMI. Detailed history and clinical examination were done for all patients and individuals regarding all rpoints related to this problem. Pelvic sonography was performed for female cases. Fasting blood samples were obtained from all cases and individuals to measure fasting blood sugar and serum insulin. Results: The mean of fasting serum insulin level was significantly elevated for acanthosis nigricans group (11.90 ± SD 2.30) in comparison to control group (7.75 ± 0.70) while there was no significant difference in the mean of fasting blood sugar between acanthosis nigricans group and control group (83.06 ± 5.82 versus 84.80 ± 7.83) respectively. Insulin level was positively correlated with the body mass index Quantitative insulin sensitivity check index (QUICKI) as a measure of insulin sensitivity was (0.332 ± 0.012) for acanthosis nigricans group, this indicates a significantly lower insulin sensitivity for acanthosis nigricans group when compared with control group (0.352 ±0.008). There was inverse correlation between QUICKI and body mass index. Conclusions: Patients with acanthosis nigricans were found to have significant decrease in insulin sensitivity i.e. increased insulin resistance with high fasting insulin level.