Seborrheic Keratoses

ByDenise M. Aaron, MD, Dartmouth Geisel School of Medicine
Reviewed/Revised Sept 2023
View Patient Education

Seborrheic keratoses are superficial, often pigmented, epithelial lesions that are usually verrucous but may occur as smooth papules.

The cause of seborrheic keratosis is unknown, but genetic mutations have been identified in certain types. The lesions commonly occur in middle age and later and most often appear on the trunk or temples. In darker-skinned people, multiple 1- to 3-mm lesions can occur on the cheekbones; this condition is termed dermatosis papulosa nigra.

Seborrheic keratoses vary in size and grow slowly. They may be round or oval and flesh-colored, brown, or black. They usually appear stuck on and may have a verrucous, velvety, waxy, scaling, or crusted surface.

Seborrheic keratoses that are large, multiple, and/or rapidly developing can be a cutaneous paraneoplastic syndrome (Leser-Trélat sign) in patients who have certain cancers (eg, lymphoma, gastrointestinal cancer).

Manifestations of Seborrheic Keratoses
Seborrheic Keratosis
Seborrheic Keratosis

Seborrheic keratoses are benign pigmented lesions. Cause is unknown. They tend to develop in older adults and have a stuck-on appearance with a verrucous, velvety, waxy, scaly, or crusted surface.

... read more

Image provided by Thomas Habif, MD.

Seborrheic Keratoses (Back)
Seborrheic Keratoses (Back)

This photo shows seborrheic keratoses (hyperpigmented lesions with a stuck-on appearance) on a patient's back.

DermPics/SCIENCE PHOTO LIBRARY

Dermatosis Papulosa Nigra
Dermatosis Papulosa Nigra

This photo shows multiple, small seborrheic keratoses on the cheekbones and forehead of a person with dark skin.

DermPics/SCIENCE PHOTO LIBRARY

Leser-Trélat Sign
Leser-Trélat Sign

Leser-Trélat sign is the rapid onset of numerous seborrheic keratoses (benign, often pigmented skin lesions with a "stuck-on" appearance).

... read more

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Diagnosis of Seborrheic Keratoses

  • Clinical evaluation

Diagnosis of seborrheic keratosis is clinical.

Treatment of Seborrheic Keratoses

  • Removal only if bothersome

Lesions are not premalignant and need no treatment unless they are irritated, itchy, or cosmetically bothersome.

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