Atrophic scars
Atrophic scars (pronounced aye TRO fick) form a depression or sunken area because of damage to the collagen, fat or other tissues below the skin. These scars are caused by: Acne, chickenpox, surgery and accidents.
Keloid and hypertrophic scars
Keloid and hypertrophic scars are dense, raised scars that are thicker than surrounding skin. They occur when the body produces too much collagen while a wound heals. They can be removed by surgery, but might return.
  • Keloid  scars occur when too many cells grow at the site of a skin injury. The resulting tissue covers the wound and some part of surrounding skin. These red-purple scars do not usually go away by themselves. They are more common in people who are African-American, Hispanic or Asian.
  • Hypertrophic scars are also raised, but they do not usually expand beyond the wound. They can fade at least partially without any treatment.