Stretch marks are usually thin, shiny, slightly indented and wrinkled lines that appear on the body after the skin has been stretched beyond its capacity to snap back. Stretch marks differ from scars because they are not composed of dense fibrotic tissue. Instead, they represent an absence of tissue - gaps in the dermis left by stretched or torn elastic fibers just beneath the skin’s surface. They occur following rapid weight gain and/or increase in body size that abruptly stretches the skin. Stretch marks first appear as deep red marks that gradually fade into a silvery white color over time. The epidermis over the stretch marks becomes thinner, giving the surface a fragile feel and appearance.