Some scars become highly visible and unattractive due to factors such as your age, scar location and size, nutrition, genetics, or infection. Both types of scars are raised. Hypertrophic scars are elevated above the surface of the skin, but confined within wound boundaries. Keloid scars are similar to hypertrophic scars, except that they extend beyond the boundaries of the original wound into surrounding skin areas. Not all scars are caused by wounds, burns, surgeries, and accidents.
Skin diseases caused by bacteria, fungus, or viruses can also result in scarring.
Acne is a good example of a skin disease that leaves scars. Stretch marks are an example of scars caused by weight change or growth. Scarring is a part of the natural healing process. Based on personal history or medical conditions, some people are more likely to develop problem scars. Two reasons for problem scarring are improper cleaning of the wound and further injury to the wound site.