Acanthosis nigricans is an incredibly common skin condition yet very few people seems to have heard of it. It appears as dark skin in body folds especially around the neck or arm pits which people normally mistake for common place hyperpigmentation. Which is why it can be distressing when it fails to respond to skin brightening treatments and may even continue to spread. This is because acanthosis nigricans is not really as a result of excess pigment deposition alone. It is actually usually a sign of an underlying medical problem. In this article, we explore what acanthosis nigricans looks like and what causes it. We’ll also review how to tell it apart from other types of hyperpigmentation and the best ways to treat it.
What is Acanthosis Nigricans & What Does it Look Like?
Acanthosis nigricans is a skin condition where dark, velvety patches develop in body folds. Although it is often grouped together with other hyperpigmentation disorders, acanthosis nigricans has distinct features. Correctly recognising these is essential for treatment. In general, acanthosis nigricans typically presents with the following characteristics:
- Appearance: There are dark, brown or greyish patches of skin with a velvety or thickened texture. The affected areas of skin usually develops a slightly raised, rippled or matte sheen.
- Location: It typically affects skin folds commonly around the neck, underarms, groin or breasts. It can also sometimes present around the knuckles or elbows.
- Behaviour: Acanthosis nigricans usually appears gradually and tends to persist or spread if you don’t treat the underlying cause. It rarely improves with pigment-suppressing treatments alone.
- Skin type: It is more noticeable in medium to deeper skin but can occur in all skin tones.
What Causes Acanthosis Nigricans?
It is best to view acanthosis nigricans as a signal rather than a primary skin disease in and of itself. This is because this skin condition occurs in response to underlying medical or internal problems. In acanthosis nigricans, the skin usually thickens and darkens due to the following triggers:
- Insulin resistance: This is the most common cause of acanthosis nigricans. Conditions like polycystic ovary syndrome (PCOS), pre-diabetes and type 2 diabetes can increase circulating insulin. This stimulates skin cell growth leading to darkening and thickening.
- Hormonal changes: Thyroid disorders, Addison’s disease, PCOS, Cushing’s syndrome and other endocrine conditions can also trigger acanthosis nigricans.
- Medications: Steroids, certain contraceptives, hormonal therapies and high-doses of niacin can all lead to this condition.
- Obesity: This is one of the most common triggers as increased friction and higher insulin levels can trigger acanthosis nigricans.
- Genetic factors: Less common but acanthosis nigricans can develop in certain inherited syndromes.
- Malignancy-associated acanthosis nigricans: Although most diseases triggering acanthosis nigricans are benign, it can sometimes be a sign of an underlying malignancy. Sudden extensive onset, especially in older people, can be associated with internal cancers and requires urgent assessment.
Acanthosis Nigricans vs Hyperpigmentation
Given that most people haven’t heard of acanthosis nigricans, they generally assume that it’s regular hyperpigmentation due to friction or genetics. However there are a few clues that can help tell them apart:
- Colour & texture: Acanthosis nigricans looks brown or grey much like other forms of hyperpigmentation especially on dark skin. The key difference is its velvety feel and thickened texture compared with PIH and melasma which are largely smooth flat patches.
- Location: Generally, acanthosis nigricans affects folds and friction areas such as the neck, armpits, breasts and groins. Melasma usually affects the face and neck whereas PIH tends to appears exactly where inflammation occurred.
- Triggers: Acanthosis nigricans usually reflects metabolic, hormonal or medication changes. Most other types of hyperpigmentation are usually due to inflammation, genetics or ultraviolet light exposure although melasma also may have a hormonal trigger.
- Behaviour over time: Normally, acanthosis nigricans persists if the underlying trigger is not treated. PIH can gradually fade with time by itself though this can be sped up with correct treatment. Melasma improves with pigment-suppressing skincare but tends to relapse with heat and sunlight.
To make things even harder, sometimes people might have acanthosis nigricans as well as other types of hyperpigmentation like PIH or melasma going on at the same time. That’s why it’s best to seek medical advice to get a proper diagnosis and correct treatment.
How to Treat Acanthosis Nigricans
The most effective treatment focuses on identifying and correcting the underlying cause as this will prevent the hyperpigmenattion and skin thickening from spreading and getting worse. In addition to this, you may also need treatment to directly target the existing pigmentation as this may not fully reverse by itself. In general the best approach for treating acanthosis nigricans involves:
- Medical evaluation: This is crucial for accurate diagnosis. Your doctor will screen for common triggers like insulin resistance, diabetes, PCOS, thyroid disease or medications. Diagnosis usually requires physical exam and blood tests though additional tests may be necessary depending on the results of these. If any medical conditions are indentified then your doctor will start you on treatment for this.
- Lifestyle management: Weight optimisation, exercise and a balanced diet can help improve insulin sensitivity which is a common trigger. Even small improvements may visibly help reduce the severity of acanthosis nigricans.
- Medication review: If symptoms began after starting medications like steroids, hormonal treatments or high-dose niacin, then your doctor may adjust your dose or offer alternatives if appropriate.
- Skincare: Products containing tretinoin, adapalene, hydroquinone, azelaic acid, ammonium lactate or urea can help fade dark marks and soften thickened skin.
- Professional treatments: Chemical peels and certain lasers may be helpful in severe cases especially where there is significant texture change.
Best Skincare Ingredients for Acanthosis Nigricans
Skincare alone cannot reverse acanthosis nigricans. However, if the underlying cause is resolved then skincare plays a vital supportive role. It can help smooth, brighten and soften the affected areas. The best skincare ingredients for acanthosis nigricans include:
- Exfoliants: AHAs like lactic acid, PHAs and higher strength urea can help reduce roughness and soften thickened skin. They can also help gently fade hyperpigmentation.
- Retinoids: Over the counter retinoids and prescription forms like tretinoin increase cell turnover which helps improve texture and brightens the skin over time.
- Azelaic acid: This gentle exfoliating acid helps with mild pigmentation, thickening redness and inflammation.
- Barrier support: Ceramides, fatty acids and niacinamide help reduce irritation and strengthen the skin barrier while stronger treatments are being introduced.
- Pigment suppressors: Ingredients such as hydroquinone, arbutin, kojic acid or cysteamine may help even tone but work best in combination with an exfoliant which can help improve skin texture.
When to Seek Medical Help
Acanthosis nigricans can be a major cosmetic concern but always remember that it is also an important clinical sign. It usually hints at an underlying medical condition. Early intervention improves the chance of reversing both the skin changes and treating the underlying trigger. As such it is really important to seek a medical review if you develop hyperpigmentation especially if there is:
- Sudden onset or rapid progression
- Involvement of unusual areas of the body like the groin, neck or other folds of skin
- Accompanying symptoms such as weight changes, fatigue, irregular periods or excessive thirst
- No improvement despite skincare and lifestyle measures
- You have a family history of or existing endocrine or metabolic diseases
Whilst common, acanthosis nigricans is the little heard of condition that is often mistaken for regular hyperpigmentation. It is however an important sign of an underlying hormonal, metabolic or medication-related trigger. Although skincare can soften and brighten the affected areas, improvement relies on identifying and treating the underlying cause.
At City Skin clinic, we are super passionate about personalised skincare. Our virtual skin clinic offers safe and effective custom skin treatments. Where appropriate our doctors use ingredients such as Tretinoin, Hydroquinone and Azelaic acid to treat skin conditions like acne, hyperpigmentation, melasma and skin ageing. Start your online consultation today. The journey towards great skin starts here.
This article is intended for general informational purposes only and is not a substitute for medical advice, diagnosis or treatment. Always consult a qualified medical provider for any medical concerns or questions you might have.
