What causes keloids?
When the skin’s surface is broken by an injury or burn, fibrous tissue grows over the wound to start the repair process and to protect the wound. An overproduction of collagen is thought to cause keloids to start growing.
If you have had a keloid scar before, you're more likely to get another. In people with keloid-prone skin, extra tissue grows and forms a smooth, hard, raised growth. A keloid may not develop for weeks or months after the injury, or it can grow quickly after the injury. The underlying cause why some people’s skin is prone to keloids is not known.
Keloids can develop after:
- A cut, puncture wound, scratch, or surgical incision
- A burn
- Tattoo or piercing
- Chickenpox sores heal
- Serious acne
- An insect bite
- Needle injection
- Consistently wearing tightly braided hair
- Shaving their face, keloids can develop in men’s beard area
- No injury to the skin, called a spontaneous keloid
Who’s at risk for keloids?
About 10% of the world’s population have keloid scars. People with these characteristics are more likely to develop a keloid after an injury:
- African, Asian, or Hispanic descent
- Darker skin
- Family history of developing keloids
- Between 10 to 30 years of age, although it can develop earlier or later; children and elderly people almost never develop a keloid after an injury
- History of having had keloids
- Pregnant women of all skin types