Some scars grow lumpy and larger than the wound they're healing – this is called keloid scarring. Anyone can get a keloid scar, but they are more common in people with dark skin, such as people from Africa and African-Caribbean and south Indian communities.
When the skin is broken – for example, by a cut, bite, scratch, burn, acne or piercing – the body produces more of a protein called collagen.
Collagen gathers around damaged skin and builds up to help the wound seal over. The resulting scar usually fades over time, becoming smoother and less noticeable.
But some scars don't stop growing, invading healthy skin and becoming bigger than the original wound. These are known as keloid scars, which affect around 10-15% of all wounds.
Keloid scars are more common on the upper chest, shoulders, head (especially the earlobes) and neck, but they can happen anywhere.
They can last for years, and sometimes don't form until months or years after the initial injury.
They're usually painless, but some can cause:
Some people feel embarrassed or upset if they think the scar is disfiguring them.
Experts don't fully understand why keloid scarring happens. They are not contagious or cancerous.
Keloid scars can sometimes develop after minor skin damage, such as burns, acne scars and even chicken pox, but they can sometimes happen spontaneously with no history of skin trauma. If you've had a keloid scar before, you're more likely to get another.
Keloid scars can affect anyone, but they're more common in people with dark skin and it's thought they may run in families. Younger people between the ages of 10 and 30 are more likely to develop them.
You can't completely prevent keloid scars, but you can avoid any deliberate cuts or breaks in the skin, such as tattoos or piercings, including on the earlobes.
Treating acne will reduce the likelihood of acne scars appearing. Avoid minor skin surgery to areas more prone to keloid scarring – the upper chest, back and upper arms – if possible.
There are several treatments available, but none have been shown to be more effective than others. Treatment can be difficult and isn't always successful.
Treatments that may help flatten a keloid include:
Other options include:
If you're bothered by a keloid scar and want help, see your doctor.
Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.