A scar results from the biological process of wound repair in the skin and other tissues of the body. When skin is damaged, scars occur. Damage to the deeper layer of the skin, the dermis, is required to produce a scar. Damage to only the epidermis, the most superficial layer of skin, will not produce a scar. Scars formation is a natural healing process during which fibrous tissues replace normal skin during an injury.

types of SCAR

Hypertrophic scars are also raised, but they do not usually expand beyond the wound. Hypertrophic scars occur when the body overproduces collagen, which causes the scar to be raised above the surrounding skin. Hypertrophic scars take the form of a red raised lump on the skin. They usually occur within 4 to 8 weeks following wound infection or wound closure with excess tension and/or other traumatic skin injuries.
Keloid scars are a more serious form of hypertrophic scarring, because they can grow indefinitely into large, tumorous (although benign) neoplasms. 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.
Atrophic scars: These form a depression or sunken area because of damage to the collagen, fat or other tissues below the skin. These are caused when underlying structures supporting the skin, such as fat or muscle, are lost. These scars are caused by Acne, chickenpox, surgery and accidents.
Stretch marks: Stretch marks (technically called striae) are also a form of scarring. These are caused when the skin is stretched rapidly (for instance during pregnancy, significant weight gain, or adolescent growth spurts), or when skin is put under tension during the healing process, (usually near joints). This type of scar usually improves in appearance after a few years.