Stretch marks are a form of scarring on the skin with an off-color hue. They are caused by tearing of the dermis, which over time may diminish, but will not disappear completely.

Stretch marks begin with reddish or purple lines, and later gradually fade to a lighter range.

Stretch marks are caused by stretching of the skin associated with increased growth or rapid weight gain.

The causes of stretch marks are:
*.Hormonal changes
*.Genetics
*.Rapid weight gain (obesity)
*.Poor diet
*.Puberty
*.Use of oral or topical corticosteroids
*.Use of topical steroids
*. Cushing's disease
*.Adrenal gland disease
*. Pregnancy

Health tips from: http://www.healthliveblog.org/2014/12/what-really-causes-stretch-marks.html