Acanthosis Nigricans, a pediatric clinical case review and discussion

Patient Presentation
A 12-year-old male came to clinic for his health supervision visit. His mother was concerned because they both couldn’t wash off the “dirt” that was on his neck and arms. She had noticed it more since the spring and summertime when he was wearing lighter clothing. He only had recess as his main activity and wasn’t doing much activity during the summertime. He ate few vegetables and many carbohydrate-heavy foods. The family history was positive for obesity, diabetes mellitus and heart disease.

The pertinent physical exam showed that his weight was 95% and height of 75%. His BMI was trending upwards and was 105%. His vital signs were normal. Skin examination showed mild darkened velvety skin along his neck/shoulders and also on his back at his axilla. He was Tanner II.

The diagnosis of an overall healthy child who had an elevated body mass index and acanthosis nigricans was made. The pediatrician discussed the importance of weight management with the family including increasing activity. The patient had not had pre-pubertal lipid testing and this was recommended along with obesity screening. The laboratory evaluation eventually returned normal for all testing.

The patient’s clinical course 3 months later showed that they had made some changes such as low-fat dairy products, but he still wasn’t eating more vegetables and fruit and had minimally increased his exercise. He had gained 2.3 kilograms. His family was again counseled about weight management. The mother asked for help with meal planning and was referred to a dietician. The medical student asked the pediatrician what other conditions were associated with acanthosis nigricans. She said she knew that insulin resistance and problems associated with it were big ones. “Usually it’s caused by obesity and insulin problems, but I know there are other conditions too that I would need to review to answer your question,” she offered.

Discussion
Acanthosis nigricans (AN) was first described in 1891 in Germany. It is a dermatologic problem characterized by “…symmetric, hyperpigmented velvety plaques with ill-defined borders, typically involving intertriginous areas.” It usually is not present at birth (but could be) and various prevalence data for the adolescent age range is 5.7-9.3%. AN is more common in the adult population and there is no gender distinction. Benign AN is usually congenital or occurs in adolescence or childhood and may be inherited as a variable penetrance autosomal-dominant trait. It is much more common in obese patients (14-66%) and up to 36% may have diabetes mellitus type 2. Hyperinsulinism also with other factors seem to be part of the etiology. Diagnosis is clinical and screening tests associated with obesity complications including Diabetes should be considered if AN is diagnosed. Overall prognosis depends on any underlying cause such as weight reduction, discontinuing causative drugs and treatment of underlying malignancy or endocrinopathy. Skin specific treatments include topical retinoids, Vitamin D analogs, chemical peels, keratolytics and possibly systemic therapies and/or procedures such as laser therapy or dermabrasion.

Learning Point
Conditions associated with AN usually fall into these major areas

Obesity and insulin resistance***
Medications
Malignancy
Endocrinopathies
- Diabetes mellitis***
- Insulin resistance***
- Acromegaly/gigantism
- Addison’s disease
- Cushing’s disease
- Hashimoto thryoiditis
- Polycystic ovary disease
- Ovarian hyperthecosis
- Pineal hyperplasia
Medications
- Insulin
- Corticosteroids
- Estrogen and combined oral contraceptives
- Growth hormone
- Nicotinic acid
- Protease inhibitors
- Testosterone and methyl-testosterone
Malignancy – Rare in the pediatric populations
- Osteogenic sarcoma
- Wilm’s tumor
- Gastrointestinal – gastrointestinal adenocarcinomas are more prevalent in the adult/elderly population
  - Esophageal
  - Gastric
  - Liver
  - Gall bladder
  - Bile duct
  - Pancreatic
- Breast
- Hodgkin and non-Hodgkin lymphoma
- Genitourinary cancer
- Kidney
- Lung
- Thyroid
Autoimmune disorders
- Dermatomyositis
- Hashimoto thyroiditis
- Systemic lupus erythematosus
- Sjorgren syndrome
- Scleroderma
Genetic/syndromic
- Ataxia telangiectasia
- Barter
- Crouzon
- Down
- Hermansky-Pudlack
- Lawrence-Moon-Bardet
- Marfan
- Phenylketonuria
- Prader-Willi
- and many others

*** strongly associated

Questions for Further Discussion
1. What causes black or brown skin lesions? A review can be found here
2. What do you do for weight loss counseling? A review can be found here
3. How much physical activity is recommended for children and youth? A review can be found here

Related Cases

Skin Pigmentation Disorders

Nutrition / Dietetics

School Ager

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for these topics: Skin Pigmentation Disorders and Obesity in Children.

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Sinha S, Schwartz RA. Juvenile acanthosis nigricans. Journal of the American Academy of Dermatology. 2007;57(3):502-508. doi:10.1016/j.jaad.2006.08.016

Maguolo A, Maffeis C. Acanthosis nigricans in childhood: A cutaneous marker that should not be underestimated, especially in obese children. Acta Paediatrica. 2020;109(3):481-487. doi:10.1111/apa.15031

Leung AKC, Lam JM, Barankin B, Leong KF, Hon KL. Acanthosis Nigricans: An Updated Review. Curr Pediatr Rev. 2022;19(1):68-82. doi:10.2174/1573396318666220429085231

Author
Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa

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