Acanthosis Nigricans and Obesity

There are certain skin conditions that are more common in people with obesity. Some of these conditions can indicate that there is an underlying disorder going on, like pre-diabetes, that needs to be checked out.

Acanthosis Nigricans

What Is Acanthosis Nigricans?

Acanthosis nigricans is a skin condition in which dark-colored areas, usually tan or brown in color, appear around the neck. These areas also can appear in the armpits and groin, and sometimes on the knees, elbows, and hands as well. Acanthosis nigricans is a sign of insulin resistance and occurs most commonly in individuals who have obesity, and weight loss is the best treatment.

It has been my experience that acanthosis nigricans appears as a darker shade or discoloration of an individual’s normal skin color. Thus, those with lighter skin may notice that acanthosis nigricans appears a yellowish-tan color, while those with deeper complexions will notice it as a darker brown discoloration.

Acanthosis nigricans can indicate the presence of diabetes or pre-diabetes, so if you notice it, be sure to show your healthcare provider right away so that you can be tested for diabetes or pre-diabetes.

Relation to Obesity

Obesity is a risk factor for pre-diabetes as well as for diabetes itself. Pre-diabetes is a syndrome of insulin resistance, in which body organs become resistant to the effects of the insulin that the pancreas does produce.

Obesity itself causes insulin resistance, which over time leads to pre-diabetes and then Type 2 diabetes, as the pancreas burns out and simply cannot make any more insulin for a resistant body that has essentially “used up” its insulin stores and production ability. The metabolic demands of obesity put great stress on the pancreas, which can lead to pre-diabetes and eventually type 2 diabetes.

Who Should Be Screened for Pre-Diabetes?

The U.S. Preventive Services Task Force (USPSTF) released guidelines regarding blood glucose (blood sugar) screening in October 2015.

According to the USPSTF, screening for blood glucose is recommended for overweight or obese adults aged 40 to 70 years. Ideally, this would be done as part of the routine health exam and cardiovascular risk assessment.

This recommendation was given with a B rating, and the Affordable Care Act mandates that recommendations with an A or B rating must be covered by health insurance (with few exceptions).

Further, according to the American Diabetes Association’s Standards of Medical Care in Diabetes—2015, the following body mass index (BMI) cut points should be used for identifying those at risk for pre-diabetes and type 2 diabetes:

  • For Caucasian and African Americans, the BMI cut point is 25 kg/m2 or higher.
  • For Asian Americans, the BMI cut point is 23 kg/m2 or higher.

BMI is a dated, flawed measure. It does not take into account factors such as body composition, ethnicity, sex, race, and age. 
Even though it is a biased measure, BMI is still widely used in the medical community because it’s an inexpensive and quick way to analyze a person’s potential health status and outcomes.

Additionally, the American Diabetes Association (ADA) recommends considering screening for type 2 diabetes in children and adolescents who are overweight or obese and who have two or more additional risk factors for the development of diabetes.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  • American Diabetes Association. Skin Complications.

  • American Diabetes Association. Standards of medical care in diabetes—2015. Diabetes Care 2015;38:supplement 1.

  • Seaquist ER. Addressing the burden of diabetes. JAMA. 2014;311:2267-68.

  • Siu AL. U.S. Preventive Services Task Force. Screening for abnormal blood glucose and type 2 diabetes mellitus: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2015;163:861-8.

By Yasmine S. Ali, MD, MSCI
Yasmine Ali, MD, is board-certified in cardiology. She is an assistant clinical professor of medicine at Vanderbilt University School of Medicine and an award-winning physician writer.