Winkles are a common type of skin condition which is caused by aging, significant weight loss or due to injury to an area of the body. A wrinkle may be defined as a fold, crease or a ridge of skin. They often appear due to aging, since the skin's elasticity reduces as a person ages. They can also be caused by habitual facial expressions (the same facial expression used over and over again), sun damage, poor hydration, smoking or various other external factors. The depletion of water within the body can also lead to significant wrinkling of the skin.