Skin darkening around the neck can be a sign of acanthosis nigricans, a condition that often points to underlying health problems. (Representational image: photo by kindel media on pexels) 
Medicine

Dark Skin Patches? What Acanthosis Nigricans Could Be Telling You

While acanthosis nigricans is often painless, it can be a red flag for serious underlying health conditions and need immediate medical attention

Dr. Abhilasha Manker, Pedodontist

A seemingly harmless darkening of the neck could be a hidden sign of a more serious health issue!

Skin darkening around the neck can be a sign of acanthosis nigricans, a condition that often points to underlying health problems. Acanthosis nigricans is a skin condition with esthetic implications but otherwise mild symptoms.

It is characterized by the darkening and thickening of certain areas of the skin, particularly around the neck, armpits, groin, and other body folds. While often harmless, it can be a sign of underlying health issues, such as insulin resistance, hormonal imbalances, or more serious conditions like cancer. Understanding the causes, symptoms, and treatment options for acanthosis nigricans is crucial for early detection and proper management.1

What is Acanthosis Nigricans?

Acanthosis nigricans typically presents as areas of skin that are darker, thicker, and sometimes velvety to the touch. The affected regions may appear grey, brown, or black, and the skin may feel rough. This condition can develop gradually and may or may not cause discomfort, itching, or an unpleasant odor.

The condition is more common in individuals with darker skin tones but can affect anyone. Although the skin changes are usually benign, they may signal deeper medical concerns.

Acanthosis nigricans typically presents around the neck, armpits, groin, and other body folds. It may cause discomfort, itching, or an unpleasant odor

Causes of Acanthosis Nigricans

  1. Insulin Resistance: One of the most common causes of acanthosis nigricans is insulin resistance. This is when the body's cells become less responsive to insulin, leading to higher insulin levels in the blood. Insulin resistance can progress to type 2 diabetes. The elevated insulin levels in the body stimulate skin cells to grow more rapidly, causing the thickening and darkening of the skin.

  2. Obesity: Being overweight or obese is another significant factor in the development of acanthosis nigricans. Excess weight increases the risk of insulin resistance, and the folds of the skin in overweight individuals may develop dark patches due to friction and moisture.

  3. Hormonal Disorders: Hormonal imbalances, particularly in people with conditions like polycystic ovary syndrome (PCOS), can also lead to acanthosis nigricans. Hormones play a key role in regulating skin growth and pigmentation, and any imbalance can trigger changes in skin texture and color.

  4. Medications: Certain medications, including hormonal therapies (like birth control pills) and steroids, can contribute to the development of acanthosis nigricans. These drugs may influence insulin levels or alter hormone levels, leading to changes in the skin.

  5. Cancer: Though rare, acanthosis nigricans can be associated with certain cancers, particularly gastrointestinal or lung cancer. When linked to cancer, the skin changes tend to occur suddenly and are more pronounced. This form of acanthosis nigricans is known as "malignant acanthosis nigricans" and is considered a paraneoplastic syndrome—where skin changes act as a symptom of an internal malignancy.

More Than Skin Deep

The most prominent symptom of acanthosis nigricans is the development of darkened, thick patches of skin, that look like thickened dark deposits over the skin, usually around the neck, armpits, groin, or other body folds. These areas may feel thickened, velvety or rough to touch, and can sometimes emit a distinct odor. These may also be accompanied with skin tags and the darkening may worsen on trying to scrub off the patches.

In more severe cases, the skin changes may be accompanied by itchiness or irritation.

More Than Skin Deep: The Health Risks of Acanthosis Nigricans

Beyond their unsightly appearance, these dark patches can often signal underlying health issues. Acanthosis nigricans itself is usually not harmful and is primarily a cosmetic concern, but it can signal underlying health risks, particularly insulin resistance, which may lead to type 2 diabetes.

Obesity, hormonal disorders, particularly in women can indicate Polycystic Ovary Syndrome (PCOS). It may exist along with increased facial hair (Hirsutism), male pattern baldness and central fat tendency.

In rare cases, it may indicate more serious conditions like cancers of gastrointestinal system.

In children and young adults with obesity, apart from insulin resistance, it may reflect high lipids and cholesterol levels. When left untreated, the root causes—such as diabetes, hormonal imbalances or high cholesterol levels—can lead to severe complications, including cardiovascular diseases. Prompt diagnosis and management of underlying health issues are key to reducing these risks.

Pregnant women with acanthosis nigricans have been found to have higher risk for gestational diabetes (pregnancy induced diabetes) and this could put them at a risk for type II diabetes or prediabetes within five years post-delivery.2

Diagnosis and Treatment of Acanthosis Nigricans

Diagnosis

Diagnosing acanthosis nigricans usually involves a physical examination by a healthcare provider. The doctor may also inquire about the patient's medical history, family history and lifestyle to identify potential underlying causes.

Additional tests may be needed to point out underlying causes, including blood tests to check for insulin resistance, glucose tolerance, dyslipidemia, hormone levels, or imaging studies to rule out cancer.

Do not wait to act until you develop diabetes, as it would be too late by then. Find out if you suffer from insulin resistance or not.
Dr. Sudhir Kumar, MD DM, Neurologist, Apollo Hospitals, Hyderabad, Telangana

Treatment

Acanthosis nigricans is a cutaneous manifestation indicative of deeper metabolic or systemic problems. Effective treatment, therefore, necessitates addressing these underlying conditions at the earliest, rather than treating the skin condition directly.3

Dr. Sudhir Kumar, MD DM, Neurologist, Apollo Hospitals, Hyderabad answered to a patients query on social media stating that, 'patients should not wait to act until they develop diabetes, as it would be too late by then.' They should find out if they are suffering from insulin resistance he emphasized.

Treatment modalities are based on managing under-lying metabolic disorders which may include:

  1. Weight Loss: For individuals with obesity-related acanthosis nigricans, losing weight can significantly reduce insulin resistance and, in turn, improve skin appearance.

  2. Managing Diabetes: In cases linked to insulin resistance or diabetes, controlling blood sugar levels through diet, exercise, and medication can help reverse the condition.

  3. Hormonal Treatment: For those with hormonal imbalances, treatment may involve regulating hormone levels, which can improve skin symptoms.

  4. Medications: Topical treatments, such as retinoids or exfoliating creams, may help improve the appearance of the skin. In cases caused by medications, discontinuing the drug under medical supervision may resolve the issue.

  5. Cancer Treatment: For malignant acanthosis nigricans, treating the underlying cancer has shown to completely resolve the skin condition.

Cosmetic Concerns:

Acanthosis nigricans is frequently resistant to treatment, leading to frustration and dissatisfaction. Treatment with topical agents like retinoids, tretinoins, Vitamin D analogs, depigmentation concoction may be advised by professionals.

Apart from this sometimes Dermabrasion or abrasive laser therapy can also be attempted. However, the long term effectiveness of these treatments are not yet confirmed.4

Acanthosis nigricans can be an early indicator of more serious health problems, especially insulin resistance or even cancer. While the condition itself is often harmless, it is important to consult a healthcare professional for proper diagnosis and treatment. By addressing the root causes, such as weight management, controlling diabetes, or treating hormonal imbalances, the skin changes can often be reversed, improving both health and appearance

References

1. Karadağ, Ayse Serap, Yi You, Retno Danarti, Safaa Al-Khuzaei, and WenChieh Chen. "Acanthosis nigricans and the metabolic syndrome." Clinics in Dermatology 36, no. 1 (2018): 48-53.

2. Darhous, Salma Alaa Ahmed, and Fatma Eldeeb. "Acanthosis nigricans, insight about management." The Egyptian Journal of Hospital Medicine 90, no. 2 (2023): 3649-3653.

3. Cheraghi, Mojtaba. "A comprehensive review of present therapies of acanthosis nigricans: Acanthosis nigricans treatments." Chronic Diseases Journal (2024).

3. Eggiman, Evan, and Steven R. Feldman. "The underlying pathogenesis of obesity-associated acanthosis nigricans: a literature review." Discover Medicine 1, no. 1 (2024): 19.

by Dr. Abhilasha Manker

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