Merck Manual

Please confirm that you are a health care professional

honeypot link

Seborrheic Keratoses

By

Denise M. Aaron

, MD, Dartmouth-Hitchcock Medical Center

Last full review/revision Sep 2020| Content last modified Sep 2020
Click here for Patient Education
Topic Resources

Seborrheic keratoses are superficial, often pigmented, epithelial lesions that are usually warty 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

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.

Lesions may be removed with little or no scarring by cryotherapy (which can cause hypopigmentation) or by electrodesiccation and curettage after local injection of lidocaine.

Click here for Patient Education
NOTE: This is the Professional Version. CONSUMERS: Click here for the Consumer Version
Professionals also read

Test your knowledge

Pressure Ulcers
Pressure ulcers (PUs) are defined as areas of necrosis and ulceration where tissues are compressed between bone and hard surfaces, such as a bed or chair. There are many risk factors for PUs, which include age > 65 years, decreased mobility, and impaired sensation, among others. Of the main factors that influence the development of PUs, which of the following contributes to PUs but is not a direct cause?  
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
 

Also of Interest

 
TOP