Dark Neck and Underarms: Guide to Acanthosis Nigricans
Medically Reviewed by Prof. Dr. Tariq Rashid
Consultant Dermatologist | 38 Years Teaching & Clinical Experience
Derma & Dental Clinic, Allama Iqbal Medical College / Jinnah Hospital, Lahore
Trained 67 Specialists in Dermatology | FCPS, MD, MCPS
Dark patches on your neck and underarms can be embarrassing and concerning. The main sign of acanthosis nigricans is dark, thick, velvety skin in body folds and creases. It often appears in the armpits, groin and back of the neck. This common skin condition affects millions worldwide and is particularly prevalent in Pakistan due to genetic factors and rising diabetes rates.
While these dark patches might look like dirt, they can’t be scrubbed away. Acanthosis nigricans is a treatable skin condition that causes dark patches on your body. It is often (though not always) a sign of prediabetes or diabetes. Understanding the causes and treatment options can help you regain confidence and improve your overall health.
What Is Acanthosis Nigricans?
Acanthosis nigricans is the name for dry, dark patches of skin that usually appear in the armpits, neck or groin. The condition creates thick, velvety patches that feel different from surrounding skin. It may look velvety or warty, or have a dirty appearance.
Key characteristics include:
- Dark brown to black coloration
- Thick, velvety texture
- Gradual development over months or years
- Symmetric appearance on both sides of body
- Usually painless (though may itch occasionally)
Most common locations:
- Neck (back and sides) – most frequent site
- Underarms (armpits)
- Groin area
- Under breasts
- Elbow and knee creases
- Knuckles and finger joints
Acanthosis nigricans occurs when certain skin cells reproduce too quickly, leading to hyperpigmentation and hyperkeratosis. The skin becomes darker due to increased pigment and thicker due to excess keratin production.
Main Causes of Dark Neck and Underarms (Acanthosis nigricans)
Insulin Resistance: The Primary Cause
Acanthosis nigricans is most commonly caused by high blood insulin levels, a condition called insulin resistance. When your body becomes resistant to insulin, the pancreas produces more insulin to compensate. This excess insulin stimulates skin cell growth and pigment production.
Risk factors for insulin resistance:
- Being overweight or obese
- Family history of diabetes
- Sedentary lifestyle
- Diet high in processed foods and sugar
- Age (increases after 40)
- South Asian ethnicity (genetic predisposition)
Those with acanthosis nigricans have higher levels of insulin than those without the condition. This connection explains why addressing insulin resistance often improves skin appearance.
Diabetes and Prediabetes:
It is often (though not always) a sign of prediabetes or diabetes. It is usually a sign that your body is making extra insulin that it cannot use well. The condition serves as an early warning sign for diabetes development.
Important connection to diabetes:
- Can appear years before diabetes diagnosis
- More common in people with family history of diabetes
- Children with acanthosis nigricans have higher diabetes risk
- Often improves when blood sugar is controlled
Hormonal Disorders:
Several hormonal conditions can trigger acanthosis nigricans:
Polycystic Ovary Syndrome (PCOS): Affects 6-12% of women in Pakistan and is strongly linked to insulin resistance. Women with PCOS often develop dark patches alongside irregular periods and weight gain.
Thyroid disorders: conditions that affect hormone levels – such as Cushing’s syndrome, polycystic ovary syndrome or an underactive thyroid can contribute to skin darkening.
Pregnancy: Temporary hormonal changes during pregnancy can cause acanthosis nigricans, which often improves after delivery.
Medications and Other Causes:
taking certain medicines – including steroids or hormone treatments like the contraceptive pill can trigger the condition.
Common medications that may cause acanthosis nigricans:
- Birth control pills
- High-dose niacin
- Corticosteroids (oral and topical)
- Some cholesterol medications
Other factors:
- Obesity (most common cause overall)
- Genetic predisposition
- Certain cancers (very rare)
- Some genetic syndromes
Treatment Options: Medical and Professional Approaches
Addressing Underlying Causes:
Treatment for AN depends on the cause. If AN is due to an underlying condition, such as diabetes or a hormonal condition, treating the condition will treat the skin problems.
For insulin resistance and diabetes:
- Weight loss (even 5-10% can make a difference)
- Low-carbohydrate, high-fiber diet
- Regular physical activity (150 minutes weekly)
- Diabetes medications when prescribed
- Blood sugar monitoring
For hormonal disorders:
- PCOS treatment with metformin or hormonal therapy
- Thyroid hormone replacement when needed
- Adjusting problematic medications
Professional Dermatological Treatments
Prescription Topical Medications:
- Tretinoin (Retin-A): Normalizes skin cell turnover
- Hydroquinone: Lightens pigmentation (prescription strength)
- Alpha hydroxy acids: Gentle exfoliation and texture improvement
- Salicylic acid: Helps with skin thickness
Advanced Procedures:
- Chemical Peels: Glycolic acid peels for texture and pigmentation
- Laser Treatments: IPL and other laser therapies for pigmentation
- Microneedling: Stimulates skin renewal and texture improvement
- Medical-grade HydraFacial: Deep exfoliation and hydration
Treatment costs in Pakistan:
- Dermatologist consultation: PKR 3,500-5,000
- Prescription medications: PKR 2,000-4,000 monthly
- Chemical peels: PKR 10,000-18,000 per session
- Laser treatments: PKR 18,000-30,000 per session
Home Care and Natural Approaches:
While not cures, these can support medical treatment:
Gentle skincare routine:
- Use mild, fragrance-free cleansers
- Daily moisturizing with ceramide-containing products
- Daily exfoliation and cleansing with AHAs and BHAs: Regular exfoliation with alpha-hydroxy acids (AHAs) and beta hydroxy acids (BHAs) can help make the skin smoother, softer, and brighter
Sun protection: One of the best ways to protect the skin from sun damage is by using sunscreen with SPF 30 or higher daily, especially important in Pakistan’s climate.
Lifestyle modifications:
- Choose loose-fitting, breathable clothing
- Use aluminum-free deodorants
- Maintain healthy weight through diet and exercise
When to See a Doctor:
Consult your health care provider if you notice changes in your skin — especially if the changes are sudden.
See a dermatologist for:
- Dark patches developing gradually
- Cosmetic concerns about appearance
- Professional treatment options
- Skin texture changes
See an endocrinologist if:
- Family history of diabetes
- Symptoms of diabetes (excessive thirst, frequent urination)
- PCOS or other hormonal symptoms
- Rapid weight gain or loss
Seek immediate medical attention if:
- If the darkening appears suddenly, consult a doctor, as it could be a sign of a more serious underlying condition
- Patches appear rapidly over large areas
- Associated with other concerning symptoms
Prevention Strategies:
If obesity is causing AN, you can help prevent the condition through weight management. A diet that helps you keep your blood sugar (insulin) levels in check can also help prevent AN.
Lifestyle prevention:
- Maintain healthy weight through balanced diet
- Regular physical activity (at least 30 minutes daily)
- Limit processed foods and refined sugars
- Stay hydrated (especially important in Pakistan’s climate)
- Get adequate sleep (7-9 hours nightly)
Skin protection:
- Use gentle, pH-balanced skincare products
- Avoid harsh scrubbing or bleaching
- Choose appropriate clothing to minimize friction
- Protect from sun exposure with sunscreen
Health monitoring:
- Regular check-ups including blood sugar testing
- Monitor for diabetes risk factors
- Manage any underlying conditions like PCOS or thyroid disorders
What to Expect: Treatment Timeline and Results
People typically see good results after treatment. The skin clears, although the dark spots may not go away completely.
Realistic timeline:
- 2-4 months: Initial improvement in skin texture with lifestyle changes
- 6-12 months: Significant improvement when underlying causes are addressed
- 12+ months: Maximum improvement, though complete reversal may not always occur
Factors affecting results:
- How long the condition has been present
- Underlying cause and severity
- Consistency with treatment
- Individual skin response
Losing weight will help acanthosis nigricans fade, and Often, weight loss, exercise and a nutritious diet help reduce insulin levels, resulting in improved skin.
Finding Expert Care in Pakistan
Derma & Dental Clinic:
- Experienced doctors in dermatology
- Specialist in skin disorders including acanthosis nigricans
- Advanced treatment options including laser and chemical peels
For diabetes care:
- Diabetes centers in major cities
- Endocrinology departments at teaching hospitals
- Specialized metabolic clinics
Important Facts to Remember:
No, acanthosis nigricans isn’t contagious. You can’t pass it to others or get it from other people. The condition is not caused by poor hygiene and cannot be scrubbed away.
Some people call it “dirty neck” and try scrubbing it or even using bleach to get rid of it. These don’t work, though, so spare yourself the bleaching.
Key points:
- Not contagious or dangerous by itself
- Often indicates underlying health issues needing attention
- Usually improves with proper treatment of root causes
- Professional evaluation recommended for accurate diagnosis
- Early treatment can prevent diabetes progression
Frequently Asked Questions
Is acanthosis nigricans a sign of diabetes? It is often (though not always) a sign of prediabetes or diabetes. It can appear years before diabetes is diagnosed and serves as an important early warning sign.
Will the dark patches go away completely? The skin clears, although the dark spots may not go away completely. Improvement depends on how long you’ve had the condition and how well underlying causes are controlled.
Can children develop acanthosis nigricans? Yes, Children may have mild itching, but this is uncommon. Insulin resistance is seen in kids who are overweight or obese and makes them more likely to develop type 2 diabetes.
How long does treatment take to work? Treating the underlying cause of acanthosis nigricans can make the dark patches of skin fade or even disappear. Most people see initial improvement within 2-4 months, with significant changes after 6-12 months.
Is the condition serious? Although acanthosis nigricans is usually harmless, it’s best to get any skin changes checked out. While the skin condition itself isn’t dangerous, it often indicates underlying health issues that benefit from medical attention.
Next Steps:
If you’re experiencing dark patches on your neck or underarms:
- Schedule medical evaluation to identify underlying causes
- Consider lifestyle modifications including diet and exercise
- Explore professional treatment options with qualified dermatologists
- Monitor overall health including blood sugar and hormonal status
- Be patient with treatment as improvement takes time
Medical Disclaimer: This information is for educational purposes only and should not replace professional medical advice. Always consult with qualified healthcare providers for diagnosis and treatment of medical conditions.
Contact Information: Derma & Dental Clinic | Phone: 03041115000 | Email: info@dermatology.pk