Scars form in response to injury to the skin. Injury can be in the form of surgery, trauma, or acne. Scars may sometimes form spontaneously. Scars can be elevated (hypertrophic or keloidal), depressed (atrophic), white (hypopigmented), dark (hyperpigmented) or red (erythematous). Depending on the type of scar and its location, some combination of laser, surgical procedure, and intralesonal injection may be used to diminish the appearance of the scar(s).