Alternative names
Hypertrophic scar; Keloid scar; Scar - hypertrophic

Keloids are an overgrowth of scar tissue at the site of a healed skin injury.

Causes, incidence, and risk factors

Keloids occur from such skin injuries as surgical incisions, traumatic wounds, vaccination sites, burns, chickenpox, acne, or even minor scratches. They are fairly common in young women and African Americans. Keloidosis is a term used when multiple or repeated keloids are produced.

Most keloids will flatten and become less noticeable over a period of several years. They may become irritated from rubbing on clothing or other forms of friction. Extensive keloids may become binding, limiting mobility. They may cause cosmetic changes and affect the appearance.

Exposure to the sun during the first year of the keloid’s formation will cause the keloid to tan darker than surrounding skin. This dark coloration may become permanent.

A skin lesion that is:

  • Flesh-colored, red, or pink  
  • Located over the site of a wound, injury, or other lesion  
  • Nodular or ridged

The lesion may itch during formation and growth

Signs and tests
Diagnosis is made on the basis of the appearance of the skin or scar. A skin biopsy may be needed to rule out other skin growths (tumors).

Keloids often require no treatment. Keloids may be reduced in size by freezing (cryotherapy), external pressure, corticosteroid injections, laser treatments, radiation, or surgical removal. It is not unusual for keloids to reappear (sometimes larger than before) after they have been removed.

Discoloration from sun exposure can be prevented by covering the forming keloid with a patch or bandaid, and by using sunblockers when spending time in the sun. These extras protection measures should be continued for at least 6 months after injury or surgery for an adult, up to 18 months for a child.

Expectations (prognosis)
Keloids usually are not medically dangerous, but they may affect the cosmetic appearance. In some cases, they may spontaneously reduce in size over time. Removal or reduction may not be permanent, and surgical removal may result in a larger keloid scar.


  • Psychological distress if keloid is large or disfiguring  
  • Recurrence of keloid  
  • Discomfort, tenderness, irritation of the keloid

Calling your health care provider
Call your health care provider if keloids develop and removal or reduction is desired, or new symptoms develop.

Johns Hopkins patient information

Last revised: December 3, 2012
by Gevorg A. Poghosian, Ph.D.

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