Acanthosis nigricans (overview) L83

Author: Prof. Dr. med. Peter Altmeyer

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Last updated on: 28.12.2023

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acanthosis nigricans; Black usury skin; dystrophia papillaris pigmentosa

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Janovsky, 1890; Politzer & Unna, 1890

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Clinically descriptive term for gray-brown, papillomatous-hyperkeratotic, mostly asymptomatic, polyetiological, large-area growths of the skin, which typically occur intertriginously, more rarely also in acral form (nose, ears, palmoplantar skin, also oral). Basically, it is a uniform cutaneous reaction in which the skin responds to various endogenous "growth" stimuli with non-specific proliferation.

Acanthosis nigricans can be:

  • idiopathic
  • reactive in obese individuals
  • in association with endocrinological diseases or pregnancy (in this case, gestational diabetes should be carefully excluded)
  • induced by medication
  • as a symptom of genetic defects
  • paraneoplastic (then often referred to as "acanthosis nigricans maligna") in connection with adenocarcinomas


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A distinction is made between:

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The pathogenesis depends on the various forms of the disease. It is assumed that growth factors are activated, e.g. through the formation and activation of growth factor receptors(epidermal growth factor receptor, insulin-like growth factor receptor and fibroblast growth factor receptor (FGFR)) with mitogenic and anti-apoptotic effects on keratinocytes. Acanthosis nigricans probably only rarely leads to the activation of a single growth factor (see growth factors below), but rather to the orchestration of several factors.

Drug-induced acanthosis nigricans is caused by the interaction of certain drugs with lipid metabolism.

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Occurring in all age groups. Men and women fall ill about equally often.

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In principle, any area of the body can be affected. However, intertrigines, in particular armpits, lateral neck and neck areas, inguinal and genitoanal region are preferentially affected. Less frequently affected are eyelids, nasal entrance, elbows, popliteal or umbilical region. Involvement of palmae, plantae, oral mucosa and tongue is mainly observed in paraneoplastic acanthosis nigricans. In obese women with hyperandrogenism (e.g. in PCOS) without diabetes mellitus, the most frequent localization is the vulvar region.

Clinical features
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Mostly symmetrical formation of initially yellow-brown to black hyperpigmentation, later extensive, velvety to verrucous intensification of the skin texture, blurred against the surrounding area. Possible development of warty hyperkeratoses, which are currently not seen as an independent clinical picture, but are a partial symptom of acanthosis nigricans, usually acanthosis nigricans maligna. The growths can form cockscomb-like ridges. The most pronounced changes are seen in the centers of the growths and in the intertriginous areas(ptychotropism).

Rarely pronounced on the mucosa, where flat, leukoplakic and rarely hyperpigmented areas form. The development of cutis verticis gyrata is rarer.

The different forms do not differ significantly from each other clinically, but the infestation is often more extensive and clinically more pronounced in the paraneoplastic variant. In addition to the classic, intertriginously accentuated appearance, hyperkeratosis of the palmae and plantae as well as the flexor sides of the fingers and toes with pachydermodactyly can also occur in the paraneoplastic variant. There are usually no subjective symptoms; itching may occur in the malignant form.

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Papillomatosis and hyperkeratosis, slight mostly irregular acanthosis, basal hyperpigmentation, partially pseudohorn cysts. No significant inflammatory infiltrate in the dermis. Discrete parakeratosis with papillomatosis and epithelial hyperplasia on the mucosa, typically without proliferation of melanocytes in the epithelium. The "malignant" and "benign" forms of acanthosis nigricans do not differ histologically.

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Clinical picture and typical localization (the neck is often affected in early stages) are diagnostically groundbreaking.

General therapy
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Symptomatically in cooperation with the endocrinologist for the treatment of a possible underlying disease. Consistent hygiene of the intertrigines. In the obesity-associated form (Addison's disease, pseudoacanthosis nigricans), the skin changes usually regress when body weight is normalised. In addition, consistent hygiene of the intertriginous areas, washing with syndets.

Notice! The exclusion of malignoma is obligatory for all forms of acanthosis nigricans!

External therapy
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Mainly symptomatic therapy. Local therapy with covering, possibly zinc-containing powder or creams for dehydration (e.g. R294, R025 ). If necessary, keratolytic external therapy with creams containing salicylic acid(e.g. R216 ) or urea(e.g. R102 or basodexan); if necessary, low doses of vitamin A acid (e.g. R256 or Cordes VAS, Airol cream).

Internal therapy
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Therapy trials with acitretin (neotigason) or isotretinoin (e.g. isotretinoin-ratiopharm; acne normin) in low dosages have been described. In case of itching use antihistamines if necessary.

Operative therapie
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In the case of papillomatous growths, electrocaustic ablation can be attempted as a palliative measure, but this is usually only temporarily effective, as the skin changes can quickly reappear postoperatively.

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Malignant form

Benign forms


in addition to the typical localizations, frequent involvement of palmae, plantae, oral mucosa, tongue and eyelids

in overweight women with hyperandrogenemia often vulva area


mostly extensive involvement, partly generalized

less extensive affection


in addition to the classic appearance, hyperkeratosis may occur, especially on palmae and plantae as well as flexor sides of fingers and toes with pachydermatoglyphy ("tripe palms")

mucous membrane involvement

more frequently

more rarely

Subjective complaints

localized or generalized itching; in mucosal papillomatosis, pain and possibly dysphagia may occur

usually none

Associated symptoms

Malignancy of the internal organs, usually gastric carcinoma. Optionally, other paraneoplastic syndromes such as Leser-Trélat sign, hypertrichosis lanuginosa, pemphigus, palmoplantar keratoses or "tripe palms" may exist.

Diabetes mellitus, insulin resistance, obesity, hyperhidrosis, fibroma pendulans, hyperandrogenemia


acute onset and rapid spread, variable course, often fading after rehabilitation of the underlying malignancy with flare-up in case of metastasis

often improvement with weight reduction or regulation of the endocrinological disorder

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Unfortunately, the terminology used for acanthosis nigricans is inconsistent. Some authors define acanthosis nigricans - referred to here as acanthosis nigricans maligna - strictly as a paraneoplastic syndrome, as originally described. The much more common benign variant - referred to here as acanthosis nigricans benigna - is referred to as pseudoacanthosis nigricans. There is no clearly recognizable trend in the international literature. There are still no definite clinical and morphological distinguishing features between these two groups. In this respect, the clinical picture must be regarded as a uniform skin reaction to different endogenous proliferation factors. The exclusion of obesity and hormonal stimuli as well as the advanced age of the (tumor) patients is helpful for the assumption of a paraneoplastic genesis.

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  2. Janovsky V (1890) Acanthosis nigricans. In: Unna PG et al (Ed.) International Atlas of Rare Skin Diseases. Volume 11, Voss, Leipzig
  3. Lenzner U et al (1998) Acanthosis nigricans maligna. Case description and literature review. Dermatologist 49: 41-47
  4. Mellor-Pita S, Yebra-Bango M, Alfaro-Martinez J, Suarez E (2002) Acanthosis nigricans: a new manifestation of insulin resistance in patients receiving treatment with protease inhibitors. Clin Infect Dis 34: 716-717
  5. Pollitzer S (1890) Acanthosis nigricans. In: Unna PG et al (Ed.) International Atlas of Rare Skin Diseases. Volume 11, Voss, Leipzig
  6. Pollitzer S (1891) Acanthosis nigricans. In: Unna PG et al (eds.) International Atlas of Rare Skin Diseases. Lewis, London, pp. 1-3
  7. Schroeder B, Ding X, Pfaff-Amesse T (2002) From HAIR-AN to eternity. J Pediatr Adolesc Gynecol 15: 235-240
  8. Schwartz RA (1994) Acanthosis nigricans. J Am Acad Dermatol 31: 1-22
  9. Stulberg DL et al (2003) Common hyperpigmentation disorders in adults: Part II. Melanoma, seborrheic keratosis, acanthosis nigricans, melasma, diabetic dermopathy, tinea versicolor, and postinflammatory hyperpigmentation. On Fam Physician 68: 1963-1968
  10. Torley D, Bellus GA, Munro CS (2002) Genes, growth factors and acanthosis nigricans. British Journal of Dermatology 147: 1096-1101
  11. Yamazaki H et al (2003) Acanthosis nigricans is a reliable cutaneous marker of insulin resistance in obese Japanese children. Pediatric Int 45: 701-705


Please ask your physician for a reliable diagnosis. This website is only meant as a reference.


Last updated on: 28.12.2023