what causes stretch marks
1 This continual tugging and stretching can cause stretch marks. 2  Stretch marks sometimes appear when you rapidly gain or lose weight. Teenagers may also notice stretch marks after a sudden growth spurt.  Corticosteroid creams, lotions, and pills can cause stretch marks by decreasing the skinâs ability to stretch.
Over time they may diminish, but will not disappear completely. Stretch marks formed during pregnancy, usually during the last trimester, and usually on the belly, but also commonly occurring on the breasts, thighs, hips, lower back and buttocks, are known as striae gravidarum. Stretch marks are caused by tearing of the dermis. This is often from the rapid stretching of the skin associated with rapid growth or rapid weight changes. Stretch marks may also be influenced by hormonal changes associated with puberty, pregnancy, bodybuilding, or hormone replacement therapy.