Hypertrophic scars	Keloids
Remain confined to border of original wound	Extend beyond border of original wound
Arise in any location; commonly occur on extensor surfaces of joints	Commonly occur on the sternal skin, shoulders and upper arms, earlobes, and cheeks
Regress with time	Grow for years
Fewer thick collagen fibers	Thick collagen
Scanty mucoid matrix	Mucoid matrix
Flatten spontaneously in time	Remain elevated more than 4 mm
Appear within one month	Appear at three months or later
Less association with skin pigmentation	More common in darker skin types