When skin is injured, fibrous tissue (called scar tissue) forms over the wound to repair and protect the injury. In some cases, scar tissue grows excessively, forming smooth, hard growths called keloids.
The exact causes of keloids is not fully understood, but it is an abnormality of wound healing. A problem in Keloid scarring is that the fibroblasts that produce collagen to make a scar, over produce collagen and the keloid continues to grow. They may not appear right away and can often begin to develop months after the initial wound has been made.
Keloids can be much larger than the original wound, and develop most often on the chest, back, shoulders, and earlobes. Keloids are equally common in women and men,
Most skin injury types can contribute to keloid scarring. This includes: