Updated 22 May 2015


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


Alternative names

Cheloid scar, or possibly hypertrophic scar, which is slightly different to a keloid.

What is a keloid scar?

A keloid scar is an overgrowth of scar tissue at the site of a skin injury. A keloid is a raised, irregular and enlarging scar that results from an excessive buildup of collagen and can occur regardless of the cause of skin damage. It may follow an injury, a burn, a surgical incision or even acne.

Persistently heavy scars called keloids have two main predisposing factors. The first is the location of the scar and the second is the patient’s genetic background.

Keloid scars are more likely to develop on the earlobe, along the line of the jaw, on the shoulders and on the skin over the breastbone. They often appear after ear piercing and are more common in the upper part of the body. Keloid scars are however rare on the eyelids, the soles of the feet, palms and genitals.

In some cases keloids are tender or itchy, or they may cause persistent infections or burning pain. Although the scar is in itself harmless, it presents a cosmetic concern on an exposed area of the body.

Keloids are often confused with hypertrophic scars. Although they look similar, there are clear differences in growth and the efficacy of treatment:

  • Keloid scars usually extend beyond the edges of the original scar and can become progressively larger. Hypertrophic scars do not.
  • Keloid scars are more common in people with dark complexions, while hypertrophic scars are more common with fair-skinned people.
  • Keloid scars rarely respond to treatment. Hypertrophic scars often improve with treatment. This means that patients who have keloid scars may undergo scar revision therapy with only a small chance of success.

Keloidosis (cheloidosis) 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, but severe keloids may become binding, limiting mobility. They may also cause cosmetic concerns.

Exposure to the sun during the first year of keloid formation will enhance pigmentation of the keloid preferentially, and the dark coloration will become permanent.

What causes keloid scarring?

Keloids occur as a result of skin injuries such as surgical incisions, traumatic wounds, vaccination sites, burns, chicken pox, acne, or even minor scratches.

Who gets keloid scars and who is at risk?

The development of keloid scars is more common in dark-skinned people. Fair-skinned people are more likely to develop hypertrophic or thick scars that eventually fade. Women are more likely to develop keloids, as are people under the age of 30.

It has also been suggested that a genetic disposition needs to exist for keloid scars to form, but the exact pattern is not known.

Heavy scarring is more likely when a wound is closed under tension or where there is an infection or bleeding after surgery. Keloids are also more likely if a foreign body is present in the wound, as may occur after an accident.

After cosmetic surgery, certain scars tend to become thicker, such as those associated with otoplasty (having ears pinned back), breast reductions and abdominoplasty (tummy tuck).

Symptoms and signs of keloid scarring

  • Flesh-colored, red, or pink skin lesions
  • Located over the site of a wound, injury, or other lesion
  • Nodular or ridged
  • Itchy during formation and growth

How is a keloid diagnosed?

Diagnosis is made on the basis of the appearance of the skin and scar. A skin biopsy is often done to rule out other skin growths or tumours.

A heavy scar is either diagnosed as a keloid or a hypertrophic scar. The distinction is important because there is no effective treatment for keloid scars, but hypertrophic scars can often be improved through scar revision. The best way to tell the difference is by examination and response to treatment.

Can keloids be prevented?

There is no known way to prevent the development of keloids in people who are prone to their formation.

How is a keloid scar treated?

Unfortunately all scars are permanent and there is no technique to remove them completely. A plastic surgeon may try to conceal a scar by "revising" it – repairing it to improve its appearance.

There is no really effective treatment for those prone to forming keloids. Hypertrophic scars, however, can often be improved by scar revision. Revision follows the 99% rule – there is a 90% chance of improvement, a 9% chance the scar will remain the same, and a 1% chance it will get worse.

As an alternative to scar revision surgery to improve keloid scars, some specialists suggest steroid injections, applications of pressure or silicone sheets, and radiation.

Intralesional steroids can be injected to flatten the keloid and Cicacare gel can be applied as a gel sheeting, although this may be expensive and the results are unpredictable. Excision and re-suturing have variable success, depending on the doctor’s expertise and the patient’s predisposition towards keloids.

As scarring is a problem in people prone to keloid formation, treating keloids surgically presents a difficult situation: the new incision leads to a new scar that commonly develops another keloid. In an attempt to prevent this, your doctor may inject steroids into the site or treat the new scar with radiation therapy.

It is possible however to reduce the size of some keloid scars by freezing.

When to call the doctor

It is advisable to consult a health care professional if a keloid scar develops or if removal/reduction is desired. Also seek help if any new symptoms develop as a result of the keloid scar.

(Reviewed by Prof Don du Toit)

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