Stretch Marks

Stretch marks are a type of scarring generally associated with pregnancy, obesity, bodybuilding, and - to a lesser extent - puberty. Stretchmarks are caused when the skin is subjected to overstretching, disrupting it's normal production of collagen. Stretchmarks first appear as reddish or purplish lines, but tend to gradually fade to a lighter color.
After childbirth or weight loss, as skin contracts to its original size, stretch marks often become much less apparent. Various methods exist to remove them, including laser treatments, dermabrasion, and topical applications (e.g. cocoa butter).