Keratosis, Seborrheic

National Organization for Rare Disorders, Inc.

Skip to the navigation


It is possible that the main title of the report Keratosis, Seborrheic is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.


  • Acanthotic Nevus
  • Keratosis Seborrheica
  • Seborrheic Warts
  • Senile Warts
  • Verruca

Disorder Subdivisions

  • None

General Discussion

Seborrheic Keratosis is a skin disorder usually characterized by discolored lesions that appear to be "stuck on" the skin surface. Warts may appear and skin is often oily or greasy. These skin lesions are sometimes mistaken for cancerous growths and tend to appear predominately during middle age. Itching, irritation, inflammations or unsightliness of lesions may require surgical removal of affected skin areas.


Symptoms of Seborrheic Keratosis are limited to discolored skin lesions that appear to be "stuck on" the skin surface. These patches may appear suddenly, may vary in size, and tend to grow slowly. They may be round or oval-shaped, and vary in color from tan, yellowish-brown to black. They may be widespread over the trunk, back, and/or shoulders. Some may be large enough to be called "giants" while others may be limited to small areas of the temples or cheeks. The skin lesions may also be waxy, scaling or crusted. They tend to become darker and larger with age.


The exact cause of Seborrheic Keratosis is not known although researchers believe some forms may be inherited as a dominant trait. Human traits including the classic genetic diseases, are the product of the interaction of two genes for that condition, one received from the father and one from the mother. In dominant disorders, a single copy of the disease gene (received from either the mother or father) will be expressed "dominating" the normal gene and resulting in appearance of the disease. The risk of transmitting the disorder from affected parent to offspring is 50% for each pregnancy regardless of the sex of the resulting child.)

Affected Populations

Seborrheic Keratosis predominately affects middle aged individuals, although in very rare cases, it can be present at birth.

Standard Therapies

Since Seborrheic Keratosis is not a form of skin cancer, treatment is not essential and removal of lesions is usually performed only to enhance comfort and/or cosmetic appearance. Treatment of Seborrheic Keratosis consists of removal of the skin lesions by scraping (curettage), sealing off blood vessels or destruction of lesions (electrodessication) with local anesthetic, shave excision, or freezing with CO2 snow or liquid nitrogen. Trichloroacetic acid may be used to eliminate lesions. Dermabrasion removal may also be performed. In most cases, scarring is not associated with removal of these skin lesions.

Investigational Therapies

Information on current clinical trials is posted on the Internet at All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222

TTY: (866) 411-1010


For information about clinical trials sponsored by private sources, contact:



Sowden JM, et al., The management of seborrheic keratoses by general practitioners, surgeons and dermatologists. Br J Dermatol. 198;139:348-49.

Pariser RJ., Benign neoplasms of the skin. Med Clin North Am. 1998;82:1285-1307, v-vi.

Lemperle G., Scratching off senile warts. Plast Reconstr Surg. 1998;101:546-47.

Marks, R, et al., Who removes pigmented skin lesions? J Am Acad Dermatol. 1997;36(5 Pt 1):721-26.


NIH/National Institute of Arthritis and Musculoskeletal and Skin Diseases

Information Clearinghouse

One AMS Circle

Bethesda, MD 20892-3675


Tel: (301)495-4484

Fax: (301)718-6366

Tel: (877)226-4267

TDD: (301)565-2966



Genetic and Rare Diseases (GARD) Information Center

PO Box 8126

Gaithersburg, MD 20898-8126

Tel: (301)251-4925

Fax: (301)251-4911

Tel: (888)205-2311

TDD: (888)205-3223


For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders, Inc.® (NORD). Cigna members can access the complete report by logging into For non-Cigna members, a copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see