Acanthosis Nigricans: Symptoms, Causes, Risk Factors, Diagnosis and Treatment
Acanthosis nigricans is a common skin condition characterized by areas of dark, thickened and velvety skin. It most often develops in body folds and creases, particularly around the neck, armpits and groin. It may also affect the elbows, knees, knuckles, palms, soles and other areas. Acanthosis nigricans itself is not usually harmful or contagious. However, it can sometimes be a visible sign of an underlying health problem, particularly insulin resistance and metabolic disorders. Therefore, new or rapidly developing dark, thickened skin should be evaluated by a healthcare professional.
When the body’s cells do not respond effectively to insulin, the pancreas may produce more insulin to compensate. Increased insulin levels can stimulate skin cells to grow more rapidly, resulting in the characteristic thickened and darkened appearance. Insulin resistance may occur in people with:
Prediabetes
Type 2 diabetes
Obesity
Metabolic syndrome
Polycystic ovary syndrome (PCOS)
However, not everyone with acanthosis nigricans has diabetes or insulin resistance.
Certain medicines may sometimes trigger or contribute to acanthosis nigricans. These can include:
Some hormonal contraceptives
Growth hormone
Certain thyroid medications
High doses of niacin
Corticosteroids and other medicines in some circumstances
Anyone who develops new skin changes after starting a medicine should discuss them with a healthcare professional rather than stopping the medicine independently.
Rarely, acanthosis nigricans can occur as a paraneoplastic condition, meaning it is associated with an underlying cancer. This form is more commonly associated with certain cancers of the digestive system, particularly gastric adenocarcinoma (stomach cancer), although other cancers can also be involved. Cancer-associated acanthosis nigricans is uncommon. It is more concerning when the skin changes:
Appear suddenly
Progress rapidly
Affect unusual areas
Are widespread
Occur in a person without an obvious metabolic or hormonal explanation
Rapidly developing or unusual acanthosis nigricans should be assessed by a doctor.
No. Acanthosis nigricans is not contagious. It cannot be spread from one person to another through touching, sharing clothes or normal physical contact.
Acanthosis nigricans itself is generally not dangerous. However, it may sometimes be an important warning sign of an underlying medical condition. For example, it may be associated with insulin resistance, prediabetes or type 2 diabetes. In rare cases, rapidly developing acanthosis nigricans may be associated with an underlying malignancy. Therefore, the skin changes should not simply be considered a cosmetic problem, particularly when they appear for the first time or change rapidly.
A healthcare professional can often recognize acanthosis nigricans by examining the affected skin. Depending on the person’s symptoms, medical history and risk factors, the doctor may recommend tests to identify an underlying cause. Possible investigations may include:
Blood glucose testing
HbA1c testing
Tests for insulin resistance or other metabolic abnormalities when appropriate
Thyroid function tests
Other hormone tests when indicated
Additional investigations based on symptoms and medical history
A skin biopsy is not usually necessary when the appearance is typical, but it may occasionally be performed when the diagnosis is uncertain. If the condition develops suddenly or has unusual features, the doctor may recommend additional investigations to determine the underlying cause.
If acanthosis nigricans is associated with insulin resistance, improving metabolic health may help prevent the condition from worsening and may gradually improve the appearance of the skin. Depending on the individual’s circumstances, a healthcare professional may recommend:
Maintaining a healthy weight
Regular physical activity
A balanced diet
Management of blood glucose levels
Treatment of prediabetes or diabetes when necessary
If acanthosis nigricans is caused by a hormonal disorder, medication or another medical condition, treating the underlying cause may improve the skin changes. If a medication is suspected to be responsible, a doctor may review the medication and consider an alternative when appropriate.
Some people may benefit from topical treatments prescribed by a dermatologist to improve the appearance or texture of affected skin.
Possible treatments may include medicines that help reduce skin thickening or improve skin cell turnover. These should be used only under appropriate medical guidance because some skin-lightening or exfoliating products can irritate the skin.
Treatment of the underlying cause is generally more important than treating the skin discoloration alone.
You develop unexplained dark, thickened or velvety skin
The patches are spreading or becoming more noticeable
Acanthosis nigricans appears suddenly
You have risk factors for diabetes or insulin resistance
The skin changes are accompanied by other unexplained symptoms
The condition develops without an obvious explanation
The skin changes are widespread or involve unusual areas
Sudden, extensive or rapidly progressing acanthosis nigricans deserves particular attention because, although rare, it can sometimes be associated with an underlying serious condition.
Not all cases can be prevented, particularly those caused by genetic conditions, certain medications or other underlying disorders. However, maintaining a healthy lifestyle may reduce the risk of acanthosis nigricans associated with insulin resistance and metabolic disorders.
Helpful measures may include:
Maintaining a healthy body weight
Eating a balanced diet
Exercising regularly
Avoiding unnecessary weight gain
Following medical advice for diabetes or prediabetes
Having appropriate health checkups when risk factors are present
Acanthosis nigricans is a skin condition that causes areas of skin to become darker, thicker and velvety. It commonly affects the neck, armpits and groin.
It can be. Acanthosis nigricans is commonly associated with insulin resistance, which can occur with prediabetes and type 2 diabetes. However, having acanthosis nigricans does not necessarily mean that a person has diabetes.
It may improve when the underlying cause is successfully treated. For example, improving insulin resistance or treating an associated hormonal disorder may gradually improve the skin changes. However, improvement can take time and may not be complete in every person.
No. Acanthosis nigricans is not simply caused by poor hygiene. Scrubbing the affected area aggressively will not treat the underlying condition and may irritate the skin.
Lifestyle measures may help when the condition is associated with insulin resistance or excess weight, but unexplained acanthosis nigricans should be medically evaluated. Avoid using strong bleaching, exfoliating or steroid-containing products without medical advice.
Usually, no. Most cases are associated with conditions such as insulin resistance and obesity. However, a rare form can be associated with an underlying cancer, particularly when the skin changes appear suddenly and progress rapidly.
A dermatologist can evaluate the skin changes. A primary care doctor or endocrinologist may also be appropriate if insulin resistance, diabetes or a hormonal disorder is suspected.
Medical Disclaimer:
This article is provided for general educational and informational purposes only. It is not intended to replace professional medical advice, diagnosis or treatment. Acanthosis nigricans can have different causes, and unexplained, rapidly developing or widespread skin changes should be evaluated by a qualified healthcare professional. Do not start, stop or change any medication based solely on information provided in this article.
