Seborrheic Keratosis

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Images of Keratosis, Seborrheic


Seborrheic keratoses are common benign growths of unknown cause seen in adults due to a thickening of an area of the top skin layer.

Who's at risk?

Although they can occur anytime after puberty, almost everyone over 50 has one or more of these and they increase in number with age. Some families have an inherited tendency to grow multiple lesions. Men and women are equally as likely to develop seborrheic keratoses. Dark-skinned people are less affected than those with light skin; a variant seen in people with dark skin is called dermatosis papulosa nigra.

Signs and Symptoms

One or more spots can occur anywhere on the body, except for palms, soles, and mucous membranes (eg, in the mouth or rectum). They do not go away. They do not turn into cancers, but some cancers resemble seborrheic keratosis.

They start as light brown to skin-colored, flat areas, which are round to oval and of varying size (usually less than a half inch, but sometimes much larger). As they grow thicker and rise above the skin surface, seborrheic keratoses may become dark brown to almost black with a "stuck on" appearance. The surface may feel smooth or rough.

Self-Care Guidelines

No treatment is needed unless there is irritation from clothing with itching or bleeding.

  • There is no way to prevent new spots from forming.
  • Some lotions with alpha hydroxyl acids may make the areas feel smoother with regular use but will not eliminate them.
  • OTC freezing techniques are available but usually not effective.

When to Seek Medical Care

If a spot on the skin is growing, bleeding, painful, or itchy, see your doctor.

Spots can be removed if you don't want them, but removal is considered a cosmetic issue and is usually not covered by insurance.

Treatments Your Physician May Prescribe

Removal can be accomplished with freezing (cryosurgery), scraping (curettage), burning (electrocautery), lasers, or with acids. The doctor might conduct a biopsy if the growth looks unusual.

Trusted Links

MedlinePlus: Skin ConditionsClinical Information and Differential Diagnosis of Keratosis, Seborrheic


Bolognia, Jean L., ed. Dermatology, pp.1697-1701. New York: Mosby, 2003.

Freedberg, Irwin M., ed. Fitzpatrick's Dermatology in General Medicine. 6th ed, pp.767-770. New York: McGraw-Hill, 2003.