There are many factors that could lead to the appearance of these kinds of scars. One must understand that factors like genetics, skin type and previous history of formation of Hypertrophic scars and Keloids are natural and unmodifiable.
Keloids usually develops after the healing of incision or skin injury. It is the result of overgrowth of scar tissues. It is characterized by raised scar that grows much larger than the original would or incision. The color could go from white, red to the color of your skin.
Hypertrophic scar is the most common among the two. It is not harmful to one’s health but it can be bothersome. People receive treatments mostly for cosmetic reasons. It is characterized by thick and raised scar that does not go beyond the original scar.