Keloids, or keloid scars are hard fibrous tissues that can appear anywhere on your body. Although the exact cause behind keloids is unknown, they do tend to develop almost abruptly for no reason.
One theory suggests that when our top skin layer is damaged, then during the healing process, collagen can sometimes collect at the area, resulting in the development of keloid scars. The scars may continue to grow for years through a slow process. Some of the most common conditions that cause the formation of keloids include insect bites, ear piercings, cuts, burns, etc.