Dark patches around the neck or underarms are often dismissed as simple pigmentation. However, doctors say these changes can sometimes signal deeper metabolic concerns. A condition known as Acanthosis Nigricans is increasingly recognised as a visible sign that something inside the body may need attention.
According to Dr S Madhuri, consultant dermatologist at Apollo Hospitals, Secunderabad, the patches seen in this condition differ from ordinary pigmentation. “The skin becomes thick, velvety and slightly raised, usually around the neck, armpits and groin. If the patch spreads gradually, feels rough, or appears alongside weight gain and fatigue, it may indicate an underlying metabolic issue rather than simple tanning or pigmentation,” she explains.
The condition is strongly linked to metabolic disorders. “Medical evidence shows a strong link between Acanthosis Nigricans, insulin resistance, and type 2 diabetes. Many patients with these patches have elevated insulin levels long before diabetes is diagnosed. Dermatologists often consider it an early warning sign, prompting screening for metabolic disorders and helping doctors detect diabetes risk earlier,” she adds.
When patients present with such symptoms, doctors begin by identifying the underlying cause. Dr K Kranthi Varma, consultant dermatologist at Renova Hospitals, Sanath Nagar, notes that, “Acanthosis Nigricans is primarily diagnosed through a physical examination by a healthcare provider, who can typically identify the characteristic dark, velvety patches in skin folds.” He explains that the condition is usually: “A symptom of an underlying systemic condition most commonly insulin resistance, obesity, or metabolic syndrome.”
Further investigation often focuses on metabolic health. Dr Vrinda Agrawal, consultant endocrinologist at CARE Hospitals, Banjara Hills, Hyderabad, explains that when such skin changes appear, doctors look at what may be happening inside the body. “I’m mostly looking at what’s going on inside the body. We usually start with a few basic blood tests like fasting glucose, HbA1c, sometimes fasting insulin — to see if insulin resistance is at play. Sometimes, also looking at cholesterol, liver function, or hormone levels. This lets us see if the skin changes are pointing to a bigger problem inside the body,” says Dr Vrinda.
Treatment often focuses on addressing the root cause rather than the skin alone. “In a lot of cases, yes. If we manage insulin resistance through diet, exercise, or medication, the skin often improves. It doesn’t happen overnight — the dark patches can take a few months to fade — but treating the root issue usually matters more than any cream or procedure,” Dr Vrinda adds.
Doctors also caution against ignoring sudden changes. Dr Madhuri notes that “If Acanthosis Nigricans appear suddenly or spread rapidly, doctors advise prompt medical evaluation.” In rare situations, she adds, “Rapidly spreading Acanthosis Nigricans in older adults without obesity may signal an underlying cancer, most commonly Gastric Cancer.”
Key aspects of this approach include:
Weight reduction: Losing excess weight is the most effective way to reverse the skin changes associated with obesity.
Dietary adjustments: Reducing sugar intake and adopting a healthier diet helps manage insulin levels.
Regular exercise:Physical activity improves insulin sensitivity, which reduces the severity of the skin disease.
Preventive benefits: Maintaining a healthy lifestyle not only helps with existing symptoms but also prevents the condition from worsening.
Myths or misconceptions about this condition:
Myth: It is caused by poor hygiene and can be ‘scrubbed off’.
Fact: Scrubbing, using harsh soaps, or trying to bleach the skin will not remove the patches and will only cause irritation, potentially making the condition worse.
Myth: It is a skin disease that needs to be treated with creams
Fact: The primary treatment is to address the root cause, which is usually insulin resistance, PCOS, or obesity.
Myth: Acanthosis Nigricans is contagious.
Fact: It is not contagious and cannot be transmitted from one person to another through contact.
Myth: It is just a cosmetic issue.
Fact: In children and adults, it is a marker for a high risk of developing type 2 diabetes.
Myth: It will go away on its own.
Doctor’s clarification: The skin changes are often reversible, but they usually require active management of the underlying condition, such as weight loss, dietary changes, or medication to lower insulin levels.
Myth: It only happens to people with diabetes.
Fact: While it is strongly associated with insulin resistance and diabetes, it can also be caused by hormonal disorders (PCOS, thyroid issues), certain medications (birth control pills, steroids, niacin), or genetic factors.
- By Dr K Kranthi Varma, consultant dermatologist, Renova Hospitals