Acanthosis nigricans is a skin condition most commonly associated with insulin resistance. It appears as thickened skin that is darkened and is found in body folds of the neck, groin, forehead and under the arms. It is not accompanied by symptoms, but it may become pruritic. Persons with other endocrine disorders such as acromegaly, Cushing’s disease, thyroid dysfunction and polycystic ovarian syndrome can also develop acanthosis nigricans.
Insulin Resistance
In persons with insulin resistance, insulin levels are often increased because cells in the body are insensitive to normal insulin levels. At high concentrations, insulin stimulates the growth of skin cells. A review article in the “Dermatology Online Journal” reports the severity of acanthosis nigricans correlates to fasting insulin levels. Therefore, acanthosis nigricans is a visual marker of high insulin levels. A study in the “Annals of Family Medicine” reported the presence of acanthosis nigricans is a risk factor for type 2 diabetes.
Obesity
Acanthosis nigricans is most often observed in obese persons. Obesity is linked to the development of insulin resistance and its progression to type 2 diabetes. A study in the “The West Virginia Medical Journal” found 37 percent of adolescents were overweight or obese, and 17 percent of this adolescent population displayed acanthosis nigricans.
Prevalence
Acanthosis nigricans is more prevalent in African Americans, Native Americans and Hispanics. An article in the “Dermatology Online Journal” stated that African Americans are 25 times more likely to have acanthosis nigricans than persons of European descent.
Treatment
A review article in the “American Journal of Clinical Dermatology” reported that metformin, octreotide, retinoids and topical vitamin D3 analogs are effective in clearing up acanthosis nigricans. Typically, acanthosis nigricans regresses with the treatment of the underlying cause.
Rare Types of Acanthosis Nigricans
Acanthosis nigricans is sometimes present with internal malignant cancers. “DermNet NZ” reports that 90 percent of these cancers originate in the stomach. Rarely, a form of acanthosis nigricans may be inherited and appears in childhood. This type is not caused by high levels of insulin, but by a mutation in another growth factor receptor.
References
- “Dermatology Online Journal”; Acanthosis nigricans: A Practical Approach to Evaluation and Management
- “The West Virginia Medical Journal”; Prevalence of Obesity, Acanthosis Nigricans and Hyperinsulinemia in an Adolescent Clinic
- “American Journal of Clinical Dermatology”; Acanthosis Nigricans Associated with Insulin Resistance
- DermNet NZ: Acanthosis Nigricans
- “Annals of Family Medicine”; Acanthosis Nigricans and Diabetes Risk Factors
