Background: Acanthosis nigricans (AN) is a skin condition characterized by darkening and thickening of skin with formation of irregular folds, usually limited to a few specific areas of the body. Recently, AN has been reported to be linked to hyperinsulinemia and obesity. The aim of the present study was to determine whether or not the presence of AN in obese Japanese children is a reliable cutaneous marker.
Methods: The authors analyzed the clinical characteristics of 439 obese Japanese children (260 boys, 179 girls; mean age 10.1 years; mean percentage overweight 51.9%), who had visited Tsuruoka City Shonai Hospital in 1990-2000. Eighty-two of the 439 children were examined using an oral glucose tolerance test (OGTT). Of these children, the authors retrospectively studied 16 subjects: eight with AN and eight without AN (age range: 10.8-13.9 years; percentage overweight range: 54.3-97.0%). They were age and percentage obesity-matched males with normal glucose tolerance during OGTT. Females with normal glucose tolerance during OGTT were excluded from the 16 subjects because the number was too small and children with impaired glucose tolerance or type 2 diabetes during OGTT were also excluded because of glucose toxicity. Eighty-two children including the 16 subjects were analyzed at their first visit for the presence or absence of AN on the posterior of the neck, and for characteristics including age, birthweight, body height, bodyweight, percentage overweight, blood pressure, liver function markers serum lipid concentrations, fasting plasma glucose concentrations and insulin concentrations shown by the results of OGTT.
Results: (1) Children with AN showed significantly more glucose intolerance including impaired glucose tolerance and type 2 diabetes compared with those children without AN, and fasting plasma insulin concentrations were most significantly correlated with the presence of AN. (2) Insulin resistance based on fasting plasma insulin concentrations was seen in significantly more children with AN than in children without AN, even in age and percentage obesity-matched subjects with normal glucose tolerance during OGTT.
Conclusions: Acanthosis nigricans could be a reliable cutaneous marker of insulin resistance in obese Japanese children.