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acanthosis nigricans
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
- endocrine disorders associated with insulin resistance
- diabetes mellitus type 2
- 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:
1) papillomatosis
2) hyperkeratosis
3) epidermis with irregular folds
4) acanthosis, variable
5) increased pigment in basal layer
6) epidermal changes may result from hyperinsulinemia
- insulin-resistance, type 2 diabetes mellitus
7) associated malignancy
- adenocarcinoma, GI or GU, stomach cancer
Clinical manifestations:
1) general
a) generally insidious onset
b) hyperpigmentation, an accentuation of normal pigmentation
c) thickened skin
d) velvety feel & appearance
e) distribution
- most commonly in intertriginous regions, especially axillae & groin
- also neck, knuckles, umbilicus, corners of mouth
- distribution may be asymmetric
2) 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
- glossitis [3]
- periorbital papillomatous thickenings
- weight loss [3]
* images [5,6]
Laboratory:
1) fasting serum glucose
2) hemoglobin A1c
Radiology:
1) Chest X-ray
2) other studies as indicated to rule out cancer
Differential diagnosis:
1) Gougerot-Carteaud syndrome
2) pityriasis versicolor
3) X-linked ichthyosis
4) retention hyperkeratosis
5) nicotinic acid ingestion
Management:
1) symptomatic
a) alpha-hydroxy acids
b) keratolytic agents
c) topical tretinoin (all-trans retinoic acid)
2) treat associated disorders
a) diabetes mellitus type 2
-> metformin
b) weight reduction if associated with obesity
3) prognosis
a) Type 1: accentuated at puberty, may regress with age
b) Type 3: may regress with significant weight loss
c) Type 4: regress when etiologic agent is discontinued
d) Type 5:
1] may preced other signs of malignancy by 5 years
2] erradication of maligancy may be followed by regression of acanthosis nigricans
Related
acanthosis
paraneoplastic dermatosis
General
skin disease (dermatologic disorder, dermatopathy, dermatosis)
Database Correlations
OMIM correlations
MORBIDMAP 147670
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
- 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
- Acanthosis nigricans (image)
American Academy of Dermatology
https://www.aad.org/public/diseases/color-problems/acanthosis-nigricans
- 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