A scar results from the biological process of wound repair in the skin and other tissues of the body. Thus, scarring is a natural part of the healing process. With the exception of very minor lesions, every wound (e.g. after accident, disease, or surgery) results in some degree of scarring. An exception to this is animals with regeneration, which do not form scars and the tissue will grow back exactly as before. Scar tissue is the same protein (collagen) as the tissue that it replaces,[1] but the fiber composition of the protein is different; he explains that instead of a random basketweave formation of the collagen fibers found in normal tissue,[1] in fibrosis the collagen cross-links and forms a pronounced alignment in a single direction. Hypertrophic scars are often distinguished from keloid scars by their lack of growth outside the original wound area, but this commonly taught distinction can lead to confusion.[2] All keloid scars are hypertrophic[2] but “only a small percentage of large scars” are keloid.[2] Phenotypic differences exist between keloid scars and hypertrophic scars.[2] Keloid scars can occur on anyone, but they are most common in dark-skinned people.[3] Keloid scars can be caused by surgery, an accident, by acne or, sometimes, from body piercings. In some people, keloid scars form spontaneously.
