Acanthosis nigricans: Darker skin in the folds of the neck is common.1 Acanthosis nigricans: Darker, velvety skin in an armpit is another common sign.2
This skin condition causes some easily recognized signs and symptoms. You may notice:
- Brown or black discoloration on your skin.
- Affected skin may feel velvety and thicker than the surrounding skin.
- Skin tags may form on the darkened skin.
- Skin can itch.
- Skin can have a bad odor.
Where acanthosis nigricans forms
A velvety, dark patch of skin can form on most areas on the body, including the:
- Back of the neck.
- Groin area (especially in skin folds and creases).
- Belly button.
- Woman’s breasts (beneath).
- Female genitalia.
Less often, a patch can form on the lips, mouth, eyelids, palms of the hands, bottoms of the feet, and nipples.
Acanthosis nigricans (AN) tends to appear slowly, taking months or years to form. If it appears suddenly, you should immediately make an appointment to see a dermatologist. When AN appears suddenly, it can be a warning sign of cancer.
Learn more about acanthosis nigricans
Image used with permission of Journal of the American Academy of Dermatology:
1J Am Acad Dermatol. 2007; 57:502-8
2 J Am Acad Dermatol. 2007;57:907-8
Sinha S, Schwartz RA. “Juvenile acanthosis nigricans.” J Am Acad Dermatol. 2007;57:502-8.
Weger W, Ginter-Hanselmayer G, et al. “Florid cutaneous papillomatosis with acanthosis nigricans in a patient with carcinomas of the lung and prostate.” J Am Acad Dermatol. 2007;57:907-8.
Yosipovitch G, DeVore A, and Dawn A. “Obesity and the skin: Skin physiology and skin manifestations of obesity.” J Am Acad Dermatol. 2007; 56:901-16.