What is NOT a characteristic of keloids?

Keloids are distinctive types of scars that arise due to an overproduction of collagen during the healing process. They are known for their irregular shape and can continue to enlarge over time, distinguishing them from other types of scars. A key characteristic of keloids is that they typically do not flatten over time; rather, they often remain raised and can be quite prominent. This persistent elevation is due to the excessive collagen formation that occurs when the body heals itself in response to an injury or wound.

So, while keloids exhibit an irregular shape, progressively enlarge, and are characterized by excessive collagen formation, they do not flatten as they mature, making that description the one that does not apply to keloids.