What are the causes of stretch marks?

Dermal tears: The layer of skin called the dermis looses elastin and collagen when there is a rapid accumulation of fat in the breasts, upper arms , thighs, abdomen, due to hormones. Weight gain, pregnancy, or other stressors on the skin where you accumulate fat. The dermis tears and it causes discoloration to the skin.

No: Stretch marks occur when the skin is stretched due to obesity or pregnancy. Then, after whatever caused the stretching of the skin goes away (delivery or weight loss)- the skin changes persist.