Sometimes stretch marks can cover large areas of the body. While pregnancy is the main cause behind stretch marks, other reasons can be sudden gain or loss in weight, rapid growth, heredity factors, stress and changes in physical conditions.
The skin consists of three main layers: Epidermis (the outer layer), Dermis (the middle layer) and Subcutaneous or Hypodermic (the deepest layer). Stretch marks form in the dermis or middle layer of the skin when the connective tissue is “stretched” beyond the power of its flexibility due to rapid expansion or contraction of the skin.
As skin is stretched, the collagen is weakened and its normal production cycle is interrupted and damaged. This ultimately results in fine scars under the top layer of the skin. Initially the marks look pink or red, but over time a thin, silvery line appears on the skin surface and a stretch mark is born.
Stretch marks appear on the skin surface when someone grows quickly, or puts on weight quickly.