What is Acanthosis Nigricans?

Acanthosis nigricans can affect anyone

That dark area found on the neck, armpits, groin and other parts of the body isn't just regular darkening. It is a skin condition called Acanthosis nigricans (AN). It looks like cracked, raised skin a tone darker than your original color.

This skin condition can be due to benign causes or even malignant.

• Benign – Obesity, genetics and metabolic disorders like Diabetes Mellitus.
• Malignant – Tumors that produce insulin-like hormones or tumor necrosis factor.

Types of Acanthosis Nigricans

There several types of this skin condition depending on the specific cause.

Obesity-associated acanthosis nigricans

The most common type of AN that commonly appears during adulthood. It is specifically caused by insulin resistance related to obesity. The insulin has a growth-like influence on the body which causes AN.

Syndromic acanthosis nigricans 

Man with Acanthosis Nigricans on his underarms

AN that is associated with a syndrome or disorder such as:

• Cushing’s syndrome
• Polycystic ovary syndrome (PCOS)
• Hyperinsulinemia
• Total Lipodystrophy

Benign acanthosis nigricans 

Also known as acral acanthotic anomaly. This can occur in healthy patients on their hands and feet. Very common for dark-skinned people.

Drug-induced acanthosis nigricans

Caused by smoking and nicotinic acid, insulin, systemic corticosteroids and several hormone replacement therapy

Hereditary benign acanthosis nigricans

Inherited AN due to an autosomal dominant trait and can occur at any age.

Malignant acanthosis nigricans

Caused by internal malignancy especially cancer in the intestines. The AN manifests in the mouth such as tongue and lips.

Mixed-type acanthosis nigricans

People with several types of acanthosis nigricans.

What to do if you have Acanthosis Nigricans

Don’t panic. Some AN are benign and idiopathic or have no cause at all.

• Go to your family doctor first to know what really caused your AN. You may be subjected to several diagnostic exams such as fasting blood sugar, ultrasound of your ovaries, abdominal diagnostic exams.
• Acanthosis nigricans can be managed with a whitening regimen such as getting rid of dark underarms.
• Removing the cause can lessen the dark skin in several days for some types of AN. If it is obesity related, try to lose weight and switching to a low carb diet. For drug induced AN, try losing the smoke or ask your doctor to switch to a new drug. For other causes such as PCOS and other disorders, treating the disorder will usually remove the AN.
• Before trying out any medication or treatment regimen, always consult your doctor!

Sources:

http://www.dermnetnz.org/systemic/acanthosis-nigricans.html

http://emedicine.medscape.com/article/1102488-overview