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Early Warning
Acanthosis nigricans (AN), a distinctive skin condition that affects
Americans of color, can help nurses identify young people at high risk
for developing type 2 diabetes-and prevent the future onset of this
serious disease
By L. Grace Freeman, RN
A growing number of youth in America are being diagnosed with type
2 diabetes, also known as non-insulin-dependent diabetes mellitus (NIDDM).
In fact, it is estimated that one in three children born in the year
2000 will develop this disease. According to the American Diabetes Association
(ADA), all population groups are at risk for diabetes, but it is more
common in Native Americans, African Americans, Hispanics and Asian Americans/Pacific
Islanders.
These are the same ethnic groups that develop a dermatological disease
called acanthosis nigricans (AN). This is an important correlation,
as AN is often a precursor to a diagnosable level of type 2 diabetes.
Individuals can easily be screened for AN, and treatment interventions
for AN are also the interventions that can prevent type 2 diabetes from
manifesting altogether. Therefore, nurses and other health care professionals
need to have a thorough awareness of how to identify this early indicator,
who is at risk for it, its correlation with type 2 diabetes and the
treatments and preventive measures for AN.
Acanthosis nigricans |
Acanthosis nigricans is the physical manifestation of hyperinsulinemia,
or insulin resistance, in body cells.1 AN
will reveal itself as dark, thick skin in areas that might be rubbed from
clothing, such as the abdomen, or in skin fold regions-e.g., the groin,
neck, armpits or knuckles.2 For this reason,
AN is also known as "black neck syndrome" in reference to the
highly visible neck discoloration, which is the reaction of the epidermis
to increased levels of insulin in the blood system.
The body produces insulin in order to store glucose. Cells can become
resistant to the insulin hormone, especially in people who do not exercise
and who have a family history of insulin resistance. This leaves the
insulin locked out of cells. Beta cells in the pancreas that produce
insulin begin to tire out and fail. Glucose in the bloodstream begins
to increase, which leads to NIDDM. If the beta cells stop making insulin
altogether, the individual could be dependent on insulin shots for the
rest of his or her life.
Children will begin to show signs of AN around the age of 11.3
Most adults with AN recall it first appearing between the ages of 10
and 12. The condition is found equally in males and females.4
The primary races affected by AN as a marker for type 2 diabetes are
Native Americans, African Americans and Hispanics. Pacific Islanders
have not been cited in the literature as having AN, but one would assume
them to be at risk based on the high rate of insulin resistance in this
population group.5 AN can also be seen in
Caucasians, though is substantially less common.
Finding Insulin Resistance Faster
Until recently, type 2 diabetes was thought to affect people age 40
and over. Today, type 2 diabetes in youth is on the rise, especially
in ethnic minority populations. For example, the ADA reports that almost
one in every two Hispanics born in the year 2000 is expected to develop
the disease. This is quite alarming, as type 2 diabetes is one of the
most expensive chronic illnesses in the U.S.
Luckily, AN is an early marker for the susceptibility to NIDDM. A dermatologist
in Chicago states that children come in daily with AN; it is the discolored
skin that brings them in.6 This highly visible
"black neck" manifestation of AN is a perfect opportunity
to educate these children and their families about lifestyle factors
that contribute to type 2 diabetes. It is the first, early signal that
the child is insulin resistant and is at risk for the cascade of detrimental
effects of diabetes. AN does not mean that the individual has diabetes,
although it does indicate that further testing should be done.
In the last 20 years, obesity among the general population has tripled,
the ADA notes. (Obesity is defined as a body mass index, or BMI, of
30 or greater.) Obesity plays a major factor in insulin resistance.
Ninety-two percent of children diagnosed as having NIDDM are obese.2
In fact, there has been such an increase in children with a BMI greater
than 30 that this generation is being dubbed Generation O.
However, as a single predictor of type 2 diabetes, AN is found to be
much more reliable than obesity alone.1 Researchers have
found there is a five times greater risk of having high fasting insulin
levels in individuals with AN versus individuals who are obese without
AN.7
Before the correlation between AN and type 2 diabetes was discovered,
diabetes in youth was diagnosed by chance when routine urine or blood
tests were performed. AN occurs before other signs and symptoms of diabetes
appear. There is typically a seven year lapse between the beginning development
of diabetes in the body and the actual diagnosis of NIDDM.2
It is important that health care providers be trained to recognize
the signs of AN so that children with this dermatological marker can
be tested for hyperglycemia. Screening for AN is non-threatening and
non-invasive. Once AN is diagnosed, preventive measures for NIDDM can
be initiated.
Screening for AN by a trained professional can be done at schools or
at clinics. Typically the neck area is screened, because it has been
demonstrated as showing the most consistent staging area for AN. Screening
the armpits can be effective in patients with normal to below-normal
weight. To help predict obesity, height, weight, hip and waist measurements
can be taken along with the topical screening for AN.
Researchers grade AN into stages, but simply the appearance of AN,
in any stage, indicates hyperinsulinemia and will respond to treatment.
Diet and lifestyle changes alone can reduce the physical presence of
AN. The dark, thickened skin will gradually disappear as insulin resistance
decreases.
Treating Diabetes Before It Happens
It is especially important that young people from the high-risk minority
populations mentioned earlier be screened for AN. Screening in youth
can help at-risk individuals prevent the development of type 2 diabetes
later in life. Experts recommend that children be screened every two
years beginning at age nine, to ensure that hyperinsulinemia is caught
early and healthy lifestyle habits can be implemented successfully.6
Communities can be educated to alert friends and family to be properly
screened if they notice the signs of AN on each other.
Education for patients diagnosed with AN should include two points:
1. Lifestyle and diet changes will decrease the discoloration on their
skin.
2. All systems in their bodies will benefit from these changes.
Increasing patients' exercise will allow insulin into their cells and
will also help glucose get out of their blood system and into their
cells. This will help all of their organs operate more efficiently.
Peripheral blood flow will be improved, including blood flow to the
eyes. Most notably, diabetic retinopathy, which sets in during early
stages of NIDDM and can cause blindness, will be improved.2
Treatment begins when the patient switches to a wholesome, well-balanced
diet and starts an exercise program. Many sources, including the American
Diabetes Association, recommend decreasing weight by 5-7% and exercising
two-and-a-half hours a week-e.g., walking briskly. These measures can
reduce an individual's risk of developing type 2 diabetes by 50%.
In conjunction with exercise and diet, in some cases oral diabetic
medications may be prescribed for patients with AN. These drugs, which
decrease glucose production from the liver and do not increase insulin
production, include Metformin®, Actos® and Avandia®. Metformin
has the added effect of metabolizing fats, which helps with weight reduction.8
Blood glucose levels should be monitored and the AN discoloration should
be evaluated throughout treatment.
Adopting a healthy lifestyle will greatly enhance the individual's
ability to fight off diabetes. Even if overall weight is not reduced,
it is important to reduce caloric intake. This in itself will decrease
cells' resistance to insulin. With exercise, the number of insulin receptors
increases, improving the body's ability to use the insulin.8
Communities can help by supporting in-school and after-school programs
that increase physical activity for kids. Offering activities that families
can participate in together would be a great asset to the health of
the community. The role of nurses and other health providers is to identify
at-risk youth and educate them about healthy choices that will help
them save themselves from the devas-tating physical effects and financial
costs of diabetes.
L. Grace Freeman, RN, graduated from the University of South Dakota
nursing program in May 2004. She plans to continue her education to
become a diabetes educator.
References
1. Mukhtar, Q., Cleverley, G., Voorhees, R.E., McGrath, J.W. (2001).
"Prevalence of Acanthosis Nigricans and Its Association with Hyperinsulinemia
in New Mexico Adolescents." Journal of Adolescent Health, Vol.
28, No. 5, pp. 372-376.
2. Glaser, N.S. (1997). "Non-Insulin-Dependent
Diabetes Mellitus in Childhood and Adolescence." Pediatric Clinics
of North America, Vol. 44, No. 2, pp. 307-337.
3. Stoddart, M.L. et al (2002). "Association of
Acanthosis Nigricans with Hyper-insulinemia Compared With Other Selected
Risk Factors for Type 2 Diabetes in Cherokee Indians." Diabetes
Care, Vol. 25, No. 6, pp. 1009-1014.
4. Stuart, C.A., Pate, C.J., Peters, E.J. (1989). "Prevalence
of Acanthosis Nigricans in an Unselected Population." American
Journal of Medicine, Vol. 87, No. 3, pp. 269-272.
5. Wijeyaratne, C.N., Balen, A.H., Barth, J.H., Belchetz,
P.E. (2002). "Clinical Manifestations and Insulin Resistance in
Polycystic Ovary Syndrome Among South Asians and Caucasians: Is There
a Difference?" Clinical Endocrinology, Vol. 57, No. 3, pp. 343-350.
6. Fuerst, M. (2003). "U.S. Supersized: Childhood
Obesity an Epidemic Posing Problems for Pediatric Derms." Dermatology
Times, March 1, 2003.
7. Stuart, C.A. et al (1986). "Insulin Resistance
with Acanthosis Nigricans: The Role of Obesity and Androgen Excess."
Metabolism, Vol. 35, No. 3,
pp. 197-205.
8. Joslin Diabetes Center (2004). "What New Oral
Medications Are Available for Type 2 Diabetes?" www.joslin.harvard.edu,
February 12, 2004.
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