Acanthosis Nigricans

Author: Victoria Young MS2, Y, Miller-Monthrope, Dermatologist/Dermatopathologist, Toronto, Canada, 2024

Definition: Acanthosis nigricans is a cutaneous disorder characterized by symmetric velvety, thickening of the skin.

Signs/ Symptoms: This results in hyperpigmentation and thickening (hyperkeratosis) of the skin, especially in intertriginous areas like the axilla, groin, inframammary, and neck. The affected skin may also feel slightly raised. 

Etiology: Acanthosis nigricans may indicate an underlying issue, such as obesity or diabetes. Early recognition is important as it can be a cutaneous manifestation of systemic illnesses. Acanthosis nigricans may rarely be associated with internal malignancies (Malignant acanthosis nigricans (MAN) particularly those of the gastrointestinal tract. This type of acanthosis nigricans however is rare and tends to be rapidly progressive and more wide-spread than typical (benign) acanthosis nigricans. (3)

Treatment: Addressing the underlying cause is the primary treatment approach, such as weight loss for obesity and managing blood sugar levels for diabetes. Topical treatments like retinoids, vitamin D analogs, chemical peels or keratolytics can be used to improve skin appearance for localized lesions.

References: Dermnet

1.     Das A, Datta D, Kassir M, Wollina U, Galadari H, Lotti T, Goldust M (2020). Acanthosis nigricans: a review.. Journal of Cosmetic Dermatology, 19(8), 1857-1865. https://dx.doi.org/10.1111/jocd.13544

2.     Leung AKC, Lam JM, Barankin B, Leong KF & Hon KL (2022). Acanthosis nigricans: an updated review.. Current Pediatric Review, 19(1), 68-82. https://dx.doi.org/10.2174/1573396318666220429085231

3.     Arellano J, Iglesias P, Suarez C, Corredoira Y, Schnettler K. Malignant acanthosis nigricans as a paraneoplastic manifestation of metastatic breast cancer. Int J Womens Dermatol. 2019 Mar 21;5(3):183-186. doi: 10.1016/j.ijwd.2019.03.002. PMID: 31360756; PMCID: PMC6637086.