Flat, pale scars are the most common type and are a result of the body's natural healing process. Initially, they may be red or dark and raised after the wound has healed but will become paler and flatter naturally over time. Hypertrophic and keloid scars occur as a result of an imbalance in the production of collagen in a healing wound. They are red or dark and raised and may be itchy or painful. Hypertrophic scars may continue to thicken for up to 6 months and may restrict movement if they are located close to a joint.
Keloids grow beyond the boundary of the original wound and can continue to grow indefinitely.
Sunken scars are recessed into the skin. Some common causes of sunken scarring are acne or chicken pox. Stretched scars occur when the skin around a healing wound is put under tension during the healing process or may be as a result of poor healing because of general ill health or malnutrition. Initially, the scar may appear normal but can widen and thin over time. Stretch marks develop when the skin is stretched rapidly, such as during pregnancy or the adolescent growth spurt.