acanthosis nigricans
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Introduction
Diffuse thickening & hyperpigmentation of the skin mostly in intertriginous regions, especially the axillae.
Etiology
(Classification)
- Type 1: benign hereditary acanthosis nigricans
- onset during childhood or puberty
- Type 2: benign acanthosis nigricans
- Type 3: pseudo-acanthosis nigricans
- complication of obesity
- obesity produces insulin resistance
- diabetes mellitus type 2
- polycystic ovary syndrome
- more commonly seen in patients with darker pigmentation
- Type 4: drug-induced acanthosis nigricans
- nicotinic acid in high doses
- diethylstibesterol in young males
- oral contraceptives
- Type 5: malignant acanthosis nigricans
- paraneoplastic syndrome
- GI adenocarcinoma (especially gastric cancer)
- urogenital adenocarcinoma
- lymphoma (less commonly)
Pathology
- papillomatosis
- hyperkeratosis
- epidermis with irregular folds
- acanthosis, variable
- increased pigment in basal layer
- epidermal changes may result from hyperinsulinemia
- associated malignancy
- adenocarcinoma, GI or GU, stomach cancer
Clinical manifestations
- general
- generally insidious onset
- hyperpigmentation, an accentuation of normal pigmentation
- thickened skin
- velvety feel & appearance
- distribution
- most commonly in intertriginous regions, especially axillae & groin
- also neck, knuckles, umbilicus, corners of mouth
- distribution may be asymmetric
- type 3
- often on inner & upper thigh as a result of chafing
- often many intertriginous skin tags 3 type 5
- hyperkeratosis & hyperpigmentation more pronounced
- hyperkeratosis of palms/soles
- involvement of oral mucosa & vermilion border of lips
- periorbital papillomatous thickenings
- weight loss[3]
Laboratory
Radiology
- Chest X-ray
- other studies as indicated to rule out cancer
Differential diagnosis
- Gougerot-Carteaud syndrome
- pityriasis versicolor
- X-linked ichthyosis
- retention hyperkeratosis
- nicotinic acid ingestion
Management
- symptomatic
- treat associated disorders
- diabetes mellitus type 2
- weight reduction if associated with obesity
- prognosis
- Type 1: accentuated at puberty, may regress with age
- Type 3: may regress with significant weight loss
- Type 4: regress when etiologic agent is discontinued
- Type 5:
- may preced other signs of malignancy by 5 years
- erradication of maligancy may be followed by regression of acanthosis nigricans
More general terms
Additional terms
References
- ↑ Color Atlas and Synopsis of Clinical Dermatology, Common and Serious Diseases, 3rd ed, Fitzpatrick et al, McGraw Hill, NY, 1997, pg 505-507
- ↑ Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 171
- ↑ 3.0 3.1 3.2 Medical Knowledge Self Assessment Program (MKSAP) 11, 14, 16, 17, 18. American College of Physicians, Philadelphia 1998, 2006, 2012, 2015, 2018.
- ↑ Harrison's Principles of Internal Medicine, 14th ed. Fauci et al (eds), McGraw-Hill Inc. NY, 1998, pg 319
- ↑ 5.0 5.1 Acanthosis nigricans (image) American Academy of Dermatology https://www.aad.org/public/diseases/color-problems/acanthosis-nigricans
- ↑ 6.0 6.1 DermNet NZ. Acanthosis nigricans (images) http://www.dermnetnz.org/systemic/acanthosis-nigricans.html
- ↑ Rashid RM, Barros BS (image) Hidden Heart Disease: 19 Dermatologic Clues You Should Know. Medscape. June 13, 2017. http://reference.medscape.com/slideshow/hidden-heart-disease-6004452