Keloid and hypertrophic scar: the difference and treatment options

A scar is part of the skin's natural healing after an injury, operation, burn or inflammation such as acne. In the first months a scar is often red or pink and slightly raised, and then it gradually fades and flattens. In some people the body produces more connective tissue than needed during healing, so the scar becomes thickened. This is called a hypertrophic scar or a keloid.

A hypertrophic scar is raised, firm and often red, but it stays within the borders of the original wound. It usually appears in the first weeks or months after an injury or operation, especially where the skin is under tension or where the wound healed slowly.

A hypertrophic scar often flattens and fades by itself over time, although this can take a while. If it is bothersome, itches or pulls, the doctor may suggest treatment to speed up and improve this process.

A keloid is a thickened scar that grows beyond the borders of the original wound and can spread onto the surrounding healthy skin. It can form even after a minor injury, such as ear piercing, a puncture wound or acne. A keloid can keep growing for months and sometimes itches, burns or hurts.

Keloids are more common in some people, especially when there is a family tendency, and on certain parts of the body, such as the earlobe, chest, shoulders and upper back. A keloid usually does not go away by itself.

Rough differences:

• A hypertrophic scar stays within the wound borders. A keloid goes beyond them and spreads onto the surrounding skin.
• A hypertrophic scar usually appears soon after an injury and often flattens over time. A keloid can appear later and keep growing for months.
• After treatment, a keloid more often comes back.

The doctor determines the difference by examination. Any skin change that grows, bleeds or changes and is not at the site of an earlier wound should be shown to a doctor, as it may not be a scar.

The doctor decides on treatment after an examination, based on the type, size and age of the scar and its location on the body. Options the doctor may suggest include:

• injection treatment, when the doctor injects a medicine directly into the keloid or thickened scar, usually in several sessions,
• silicone gel or sheets applied to the scar for a longer period,
• pressure on the scar with special garments or dressings, for some scars,
• surgical scar revision, when the scar is cut out and the skin carefully stitched again so that the new scar is narrower or less noticeable.

Several methods are often combined. At Maja Hospital the group of procedures for scars includes injection treatment of keloids and thickened scars and surgical scar revision. Treatment does not remove a scar but makes it flatter, softer or less noticeable, and a keloid can come back even after treatment.

It is not possible to prevent a scar completely, but good wound care helps:

• keep the wound clean and care for it as the doctor advises,
• avoid stretching the wound and effort that pulls on it while it heals,
• do not scratch or pick off scabs,
• protect a new scar from the sun, as it can darken,
• if you have had a keloid before, tell the doctor before any operation or ear piercing.

If you notice that a scar is growing, getting thicker or itching, see a plastic surgeon.