Acanthosis nigricans and insulin resistance

This study of 30 patients investigated the correlation between physical findings of acanthosis nigricans (AN) and IR.
Patients at a private dermatology clinic with a BMI ≥25 and signs of AN were invited to participate. Digital images of the neck and axilla were taken, and a history including familial history of type 2 diabetes. Fasting serum glucose and insulin values were obtained.

The images were assessed and posterolateral neck pigmentation and/or texture and axillary pigmentation and/or texture recorded.

The homeostasis model assessment of IR (HOMA-IR) was used. IR is considered to be present in non-diabetic patients if HOMA-IR is >1.775.

The results indicated that HOMA-IR was greater than 1.775 for 25 of 30 patients (83%). Posterolateral neck texture had the highest sensitivity (96%) and OR (17.3) for IR compared with neck pigment or axillary texture and pigment. The authors propose the term ‘insulin neck’ to describe this potential marker for IR and suggest all patients with raised BMI should be examined for it.

Payne KS, Rader RK, Lastra G et al. JAMA Dermatol 2013; 149: 875-7