In general, scarring means that an injury is improving, and most scars eventually fade over time. However, as WebMD explains, some scars cause damage of their own.

Here are three types of scars that may require medical treatment for impaired function or disfigurement.

Keloid scars

When extra scar tissue builds up around the wound, it can become a growth that does not go away after the injury heals. These keloid formations go beyond the area of the wound and may cause problems with movement.

If a scar causes impairment or is in a visible location that causes emotional distress, a doctor may recommend removing it through cryotherapy, steroid injections or surgery.

Contracture scars

After a burn, a contracture scar may form. This type of scar often hampers movement because it tightens the skin. A contracture scar may also affect structures such as muscles and nerves beneath the skin.

People who have suffered burns often require skin grafts to prevent impairment and promote healing. They may also need further surgery and physical therapy to prevent loss of mobility.

Hypertrophic scars

Healthline explains that, like keloid scars, hypertrophic scars are typically thick and rise above the rest of the skin. They do not spread past the original wound site, but they may restrict movement, especially if they develop over a joint.

They form due to the overproduction of collagen. Burn injuries, wounds that should have stitches but do not, and infected or inflamed wounds are those most likely to develop hypertrophic scars. Most people do not suffer physical impairment from this type of scars.