Rare diseases · Sign or symptom
Acanthosis nigricans
Darkened and thickened skin
HP:0000956
What it means
A dermatosis characterized by thickened, hyperpigmented plaques, typically on the intertriginous surfaces and neck.
Acanthosis nigricans is seen in a variety of syndromes including those characterized by insulin resistance or fibroblast growth factor receptor (FGFR) mutations, and may also occur as an adverse effect of several medications that promote hyperinsulinemia.
Rare diseases that can present with this47
Very common80–99%
10- Acanthosis nigricans-insulin resistance-muscle cramps-acral enlargement syndrome
- AKT2-related familial partial lipodystrophy
- CIDEC-related familial partial lipodystrophy
- Costello syndrome
- Crouzon syndrome-acanthosis nigricans syndrome
- Cutis gyrata-acanthosis nigricans-craniosynostosis syndrome
- Insulin-resistance syndrome type B
- LIPE-related familial partial lipodystrophy
- Retinitis pigmentosa-intellectual disability-deafness-hypogonadism syndrome
- Severe achondroplasia-developmental delay-acanthosis nigricans syndrome
Common30–79%
10Sometimes5–29%
25- 14q11.2microduplication syndrome
- Achondroplasia
- Acquired generalized lipodystrophy
- Acquired hypertrichosis lanuginosa
- Acromegaly
- Bazex syndrome
- Cognitive impairment-coarse facies-heart defects-obesity-pulmonary involvement-short stature-skeletal dysplasia syndrome
- Congenital generalized lipodystrophy
and 17 more in this range
The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions, and Orphanet separately records 1 disease where this sign is specifically absent. A sign on this page is a conversation to have with a clinician, not a conclusion.
Part of the broader category
Also called: Keratosis nigricans
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Start free with EleplanThis page uses the Human Phenotype Ontology (2026-06-23) — Human Phenotype Ontology Consortium, hpo.jax.org. Disease associations from Orphanet (INSERM), CC BY 4.0. Content is educational and is not medical advice.