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Acanthosis Nigricans

Velvety hyperpigmented skin thickening typically in body folds associated with insulin resistance, obesity, and rarely internal malignancy.

Written by: Saygı Hospital Health Guide Editorial Board
Last updated:

This content has been compiled by the Saygı Hospital Health Guide Editorial Board and is periodically reviewed by a specialist physician.

References (5)

This content is for informational purposes only and does not constitute medical advice. You can book an appointment at our Dermatoloji department. Book Appointment →

What is Acanthosis Nigricans?

Acanthosis nigricans (AN) is a cutaneous condition characterized by hyperpigmentation, papillomatous hypertrophy, and velvety thickening of skin most often in flexural areas; reflects insulin-mediated stimulation of keratinocyte and fibroblast IGF-1 receptors.

Classified as benign (genetic), obesity-associated (most common), drug-induced (oral contraceptives, niacin, corticosteroids), syndromic (HAIR-AN, Crouzon, Bloom syndrome), and malignant (paraneoplastic, usually gastric adenocarcinoma).

Strong association with insulin resistance and metabolic syndrome — present in 74% of obese adults and 40% of obese adolescents; sudden onset in lean adults with mucous membrane involvement, palms and soles affected, and rapid progression should prompt malignancy workup.

Symptoms

Velvety thickening of skin in folds
Brown to black hyperpigmentation
Papillomatous warty surface texture
Common sites: neck, axillae, groin, knuckles
Asymptomatic but cosmetically bothersome
Skin tags often coexisting
Sudden extensive form raises malignancy concern

Risk Factors

Obesity and metabolic syndrome
Type 2 diabetes mellitus and prediabetes
Insulin resistance and hyperinsulinemia
Polycystic ovary syndrome (PCOS)
Family history and Hispanic, African American, Native American ethnicity
Medications: oral contraceptives, niacin, corticosteroids, insulin
Internal malignancy (gastric adenocarcinoma) for malignant variant

When to See a Doctor?

If you experience any of the following symptoms, seek medical attention promptly:

  • New darkening and thickening of skin in folds
  • Sudden extensive onset in non-obese adult
  • Mucous membrane, palm, or sole involvement
  • Associated weight loss and systemic symptoms
  • Family history of metabolic disease
  • Children and adolescents with metabolic concerns
  • Persistent despite weight management

Treatment Methods

01
Weight loss and metabolic syndrome management
02
Insulin resistance treatment (metformin) when indicated
03
Topical keratolytics — urea, salicylic acid, retinoids
04
Topical retinoids (tretinoin, adapalene) for cosmetic improvement
05
Calcipotriol cream and other vitamin D analogs
06
Discontinuation of causative medications
07
Malignancy workup for sudden severe extensive cases

Which Department to Visit?

You can visit our Dermatoloji department for these complaints. Our specialist physicians will create the most suitable treatment plan for you.

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Health Disclaimer: The information on this page is prepared for general informational purposes only. It does not replace medical diagnosis and treatment. Please consult your physician for your complaints. Saygı Hospital does not accept responsibility for actions taken based on the information on this page.