Keloids are raised, reddish-purple, nodular scars that are much firmer to the touch than hypertrophic scars. Keloids are the result of uncontrolled scar healing that the body does not stop once the wound is healed. The difference between keloids and hypertrophic scars is that keloids extend beyond the boundaries of the original injury site, encroaching upon surrounding uninvolved healthy tissue. Keloids can result from seemingly innocuous activities such as ear piercing and tattoos and, unlike hypertrophic scars, keloids do not regress over time. In fact, many will continue to slowly grow for years, causing uncomfortable itching and tenderness. While keloids can occur in all skin types, they are generally more common in darker skin. Keloids are one of the most difficult scar problems to successfully treat.