Acanthosis nigricans
Definition
Acanthosis nigricans is a skin disorder
characterized by dark, thick, velvety skin in body folds and creases.
Causes
Acanthosis nigricans can affect otherwise
healthy people, or it can be associated with medical problems. Some cases are
genetically inherited. It is most common among people of African descent.
Obesity can lead to acanthosis nigricans, as can
many endocrine disorders. It is frequently found in people with diabetes.
Some drugs, particularly hormones such as human
growth hormone or oral contraceptives ("the pill"), can also cause
acanthosis nigricans.
People with lymphoma or cancers of the
gastrointestinal or genitourinary tracts can also develop severe cases of
acanthosis nigricans.
Symptoms
Acanthosis nigricans usually appears slowly and
doesn't cause any symptoms other than skin changes.
Eventually, dark, velvety skin with very visible
markings and creases appears in the armpits, groin, and neck. Sometimes, the
lips, palms, soles of feet, or other areas may be affected.
Exams and Tests
Your physician can usually diagnose acanthosis
nigricans by simply looking at your skin. A skin biopsy may be needed in
unusual cases.
If no clear cause of acanthosis nigricans is
obvious, it may be necessary to search for one. Your physician may order blood
tests, an endoscopy, or x-rays to eliminate the possibility of diabetes or
cancer as the cause.
Treatment
Because acanthosis nigricans itself usually only
causes changes to the appearance of the skin, no particular treatment is
needed.
It is important, however, to attempt to treat
any underlying medical problem that may be causing these skin changes.
Outlook (Prognosis)
Acanthosis nigricans often fades if the cause
can be found and treated.
When to Contact a Medical Professional
Call your physician if you develop areas of
thick, dark, velvety skin.
References
Morelli JG. Diseases of the Epidermis. In:
Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier;
2007:chap. 656.
