Insulin resistance in various grades of acanthosis nigricans

Insulin resistance (IR) is a metabolism disorder that contributes to the pathophysiology of acanthosis nigricans (AN). In turn, AN is a self-determining risk factor and cutaneous marker of IR. However, conflicting evidence makes the AN-IR relationship debatable and open to exploration. If established, it could provide opportunities for early diagnosis and management of IR before the onset of diabetes mellitus and its complications by screening AN patients. This study investigates the prevalence of IR among AN patients and evaluates the association between IR and AN severity.

Eighty-seven patients, 18 to 60 years old, with untreated AN and absence of diabetes mellitus, underwent detailed history, systemic, and cutaneous examinations, as well as measurement of their body mass index (BMI), waist and hip circumference and their ratio (WHR), fasting blood glucose (FBG) and lipid profile, fasting serum insulin levels, and quantitative insulin-sensitivity check index (QUICKI). Severity of the neck lesions was graded according to Burke et al.'s grading system.

AN was noted most commonly in younger age groups with 93.1% of the cases younger than 45. All patients had lesions on the neck, and 63.3% of the cases had multiple site involvement. Nearly 84% of the cases were overweight or obese. AN grades exhibited a significant positive association with BMI (p = 0.002) and WHR (p = 0.016). High IR (< 0.35 QUICKI) was seen in 55 (63.2%) AN patients. IR, QUICKI, and triglyceride levels showed no significant association with AN severity and the number of AN lesion sites (p > 0.05). LDL levels (p = 0.02) and WHR (p = 0.049) showed a significant positive association with the number of AN lesion sites, but not with AN severity grading (p > 0.05).

IR is present in AN patients, but the association between IR and AN severity is not significant enough to qualify AN as a screening tool for IR.