Seborrheic keratosis

Causes, incidence, and risk factors

Seborrheic keratosis is a benign form of skin tumor. The cause is unknown.
The condition commonly appears after age 40 and tends to run in families.

Symptoms

Symptoms are skin growths that:

• Are located on the face, chest, shoulders, back, or other areas
• Are usually painless, but may become irritated and itch
• Are yellow, brown, black, or other colors
• Have a slightly raised, flat surface
• May have a rough or wart-like texture
• Often have a waxy surface
• Have a round-to-oval shape
• May have a “pasted-on” appearance
• May be single, but are usually many growths

Signs and tests

Diagnosis is mainly based on the way the growths appear. A skin lesion biopsy may be used to confirm the diagnosis.

Treatment

Treatment is usually not needed unless the growths become irritated or are unsightly.

If treatment is needed, growths may be removed with surgery or freezing (cryotherapy).

Expectations (prognosis)

Removing the growths is simple and usually does not cause scars. However, growths on the trunk often leave the skin lighter colored.

Growths usually do not return after they are removed. However, people who tend to get this condition may develop more growths in the future.

Complications

• Irritation, bleeding, or discomfort of growths
• Misdiagnosis (it may be difficult to tell apart from cancerous melanoma in some cases)
• Psychological distress from change in appearance

Calling your health care provider

Call for an appointment with your health care provider if you have symptoms of seborrheic keratosis.

Also call if you develop new symptoms, including:

• A change in the appearance of the skin growth
• New growths
• A growth that looks like a seborrheic keratosis, but it is the only growth or the growth has irregular borders and color. Your health care provider will need to determine whether the growth is melanoma.

References

1. Habif TP, ed. Clinical Dermatology. 5th ed. Philadelphia, Pa: Mosby Elsevier;2009: pp 776-783.
2. Brodsky J. Management of benign skin lesions commonly affecting the face: actinic keratosis, seborrheic keratosis, and rosacea. Curr Opin Otolaryngol Head Neck Surg. 2009;17:315-320.

Reviewed by: Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington School of Medicine. Also reviewed by Kevin Berman, MD, PhD, Atlanta Center for Dermatologic Disease, Atlanta, GA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.