Scars are the result of the healing process that the skin undergoes when it attempts to repair a wound. Scars vary in shape, color and composition. Some scars are pale and flat, while others are dark in color and appear raised. Hypertrophic scars are raised, and appear red or dark in color.
When a wound damages the skin, the type of scarring depends on the extent of the injury. Superficial injury only affects the outermost layer of skin, called the epidermis, and such injury results in minimal scarring. If the injury penetrates deeper than the epidermis, to the underlying dermis, the damage is more severe, and the scarring is more pervasive.
Tissue beneath the epidermis heals by forming collagen fibers. Collagen is a protein produced in the body. Collagen formation is what causes a noticeable scar.
Some people tend to develop hypertrophic scars more readily than others. Hypertrophic scars appear more frequently in young people and people with dark skin, although that does not diminish their appearance in older people, and people of all skin types.