What are stretch marks?
Stretch marks are fine lines on the body that occur from tissue under your skin tearing from rapid growth or over-stretching. It is a common condition that does not cause any significant medical problems but can be of cosmetic concern for some people. Other names for stretch marks are striae distensae, striae atrophicans, striae rubra (which are red) and striae alba (white). There are two basic varieties of stretch marks: white and red. Older, mature stretch marks are commonly white or
silver-colored; newer stretch marks tend to be reddish or purple in color. Light-based technologies are now available to treat both types of stretch marks non-invasively, allowing them to gently fade into memory — where most people think they belong.
Stretch marks are a normal part of puberty for most girls and guys. When a person grows or gains weight really quickly (like during puberty), that person may get fine lines on the body called stretch marks. Stretch marks happen when the tissue under the skin is pulled by rapid growth or stretching. Although the skin is usually fairly elastic, when it's overstretched, the normal production of collagen (the major protein that makes up the connective tissue in your skin) is disrupted. As a result, scars called stretch marks may form.
Stretch marks closely resemble scars. In fact, stretch marks are the most common types of skin lesions. About 90% of pregnant women get stretch marks. They also affect 70% of adolescent females and about 40% of young males. In medical terminology, stretch marks are called striae. Mature stretch marks are devoid of color, and newer stretch marks are often red or purplish in color. Stretch marks develop when the skin is excessively stretched, damaging the collagen fibers and proteins in the underlying skin layer called the dermis. Scientists believe that shattering of collagen leads to dilation of small blood vessels (called capillaries) that results in red or purple-colored early stretch marks. Inflammation and collagen remodeling may lead to the loss of pigment-producing, melanocyte cells or obscuring of melanin pigment. Over time, this lack of pigment results in the white or hypopigmented scars that most people associate with mature stretch marks. Stretch marks are a form of leukoderma.
Growth spurts and sudden or excessive weight gain cause stretch marks to form in young people. Young women commonly get them on their breasts, thighs, hips and buttocks. Young men often develop stretch marks from participating in certain body-altering sports such as weightlifting or from the use of dangerous bodybuilding steroid drugs. Women commonly develop stretch marks on their lower abdomen in the last months of pregnancy.
There is nothing that can prevent the formation of stretch marks — especially during pregnancy or during a growth spurt. Creams and lotions may ease the itchy sensation associated with stretch marks, but they won't keep them from forming. The science behind what actually causes striae distensae (stretch marks) to develop is still a bit hazy with a lot of the research being contradictory. It has been suggested that the term stretch mark is a bit of a misnomer and that stretch marks are not caused by the stretching of the skin but by an increase of a hormone called glucocorticoids. During adolescence, pregnancy, with obesity, weight lifting and Cushing’s disease there is an increased level of this hormone circulating through the blood stream.
The glucocorticoids affect the dermis (the middle layer of the skin) by preventing the formation of collagen and elastin fibers that are needed to keep skin firm. Once this happens there is a lack of supportive material as the skin is stretched and small tears can appear in the dermis. During this process the epidermis is also affected as it becomes thinner and flatter which makes the defects in the dermis more visible. The actual stretching of the skin may determine where the marks will emerge and also what direction they will run in.