Not all scar tissue is raised. There are three different types of scars --- atrophic, hypertrophic, and keloidal. Atrophic scars are depressed and cause a valley or hole in the skin. Hypertrophic scars are elevated and will subside with time. Keloids are actually non-malignant tumors formed by scar tissue that exceeds the boundaries of an original incision or injury. Keloidal scars are elevated, expansive and continue to grow. In addition to appearance, location and orientation are also important considerations in determining scar type. If a scar is thickened, does not invade normal tissue, and lies across the relaxed skin tension lines (creases in the skin), then it is a hypertrophic scar. If it is elevated and invading normal tissue, then it is a keloid scar. All types of scarring can occur on all areas of the body, but some areas such as the chest, knees and elbows are more likely to scar. (Source: Texas ENT Consultants. LLC)