Where Do Stretch Marks Appear?
Stretch marks affect people of all ages and can appear on multiple parts of the body.
They can be a result of rapid growth, weight gain, pregnancy, and more. These marks are permanent, as much as we wish they were not.
However, knowing that many people have them all over their body can help reduce some of the stigma surrounding stretch marks.
- Tights and hips
- Upper arms
- Lower back
What Causes Stretch Marks
Stretch marks are caused by a tearing of the dermis, or the inner layer of skin that is composed of connective tissue and cushions and protects the body from stress.
The marks typically are from a quick growth or weight change. A study in the American Journal of Obstetrics and Gynecology found that hormones such as estrogen and cortisone can soften skin fibers and increase the chance of getting stretch marks.
When the body grows at a normal pace, those fibers in the dermis expand and stretch slowly. When that growth is accelerated, those fibers get stretched and break.
The appearance of stretch marks can vary from reddish purple lines when they first appear, as there are blood vessels showing through the layer of broken dermis.
They gradually turning into white lines that take on an almost silver appearance as those blood vessels fade and fat underneath the skin takes its place. The longer they are there, the more they fade and can be nearly invisible.
Another study that compared skin biopsies from regular-skin and stretch-mark skin samples found that there was less elastin and protein in the skin of people with stretch marks compared to non-stretch mark skin.
Certain medical conditions can also cause stretch marks. Marfan syndrome, a genetic condition that affects the body’s connective tissues, causes stretch marks that are not related to weight gain but rather strictly rapid growth.
People with Marfan syndrome are tall with long limbs and extremely flexible joints. The disease causes weakness and decreased elasticity in the connective tissue.
Cushing’s syndrome is another disease that causes stretch marks due to rapid weight gain from the disease itself. Cushing’s syndrome is characterized by the overproduction of the hormone cortisol, which causes rapid weight gain in the stomach. The hormone also causes the skin to be more fragile and susceptible to bruising and scarring.
The use of steroids can also make you more susceptible to stretch marks. They decrease the collagen levels in the skin, which makes skin both strong and elastic.
Where Stretch Marks Appear Most Commonly?
The stomach is one of the most common places on the body for stretch marks. The marks are either from weight gain or pregnancy.
About 90% of women will get stretch marks after their sixth or seventh month of pregnancy, according to the American Academy of Dermatology.
During a pregnancy, a woman gains an average of 30 pounds over nine months. Both the amount of weight gained and how fast the weight is gained play a role in the formation of stretch marks. The skin of the stomach cannot keep up with this rapid growth, and thus stretch marks form.
Though there are many types of creams and lotions available that purport to prevent stretch marks for pregnant women, there is no scientific evidence that they are effective.
A woman’s skin can get itchy from this rapid growth, and staying hydrated by drinking water and using a regular moisturizing lotion can help keep this at bay.
Weight gain is another reason the stomach is a place stretch marks appear the most. Similar to what happens in pregnant women, the skin cannot keep up with the growth associated with fat accumulation in the belly.
Losing weight will not make stretch marks go away, in fact, losing weight can make them more prominent and scar-like. Your skin will retract but the scars made from stretch marks are there to stay (Source).
Breasts are another body part prone to rapid growth, particularly during puberty and pregnancy.
Hormones cause the breasts to get larger during pregnancy, and they stay enlarged even after birth as long as the mother is breastfeeding.
Weight gain of the breasts also typically happens during a short amount of time at the end of pregnancy, making it an easy place for stretch marks to develop.
Girls can also experience rapid breast growth as they go through puberty. Hormones associated with puberty can also create an environment ripe for the creation of stretch marks.
The good news about stretch marks that form during puberty is that barring any further rapid weight gain, these scars may fade over time so that they are nearly invisible.
Stretch marks that are found on the upper arm area are most commonly caused from rapidly gaining muscle. This is called muscle hypertrophy, or an increase in muscle mass.
The stretch marks are typically found where the deltoid muscle is (above the armpit) and the inner portion of the biceps (inner arms).
If a person becomes extremely obese and gains enough weight that it also collects in the upper arms, stretch marks could develop there as well.
Thighs and hips
The thighs are another place where people gain weight easily and quickly. People with ‘pear-shaped’ bodies tend to gain weight first in their hips and thighs. Stretch marks appear the most on the inner thighs and the outer thighs close to the hips.
Stretch marks on the hips can come from pregnancy as the skin grows to accommodate the baby’s growth.
These appear on the side of the hips and on the back, near the buttocks. Stretch marks can appear in these locations in people who have gained weight as well.
Stretch marks found on the buttocks are more often than not a result of rapid weight gain.
They do not appear on one part of the buttocks more than the other, but they can be difficult to hide when wearing a swimsuit.
Stretch marks on the lower back usually appear in tandem with ones on the buttocks, as they are typically located near the small of the back. These scars are more associated with rapid growth during puberty as the torso gets longer.
They can also come from a massive weight gain, as weight does not typically collect on the lower back unless someone is very overweight or obese.
You can see that stretch marks appear the most on the body in places that tend to gain weight easily or grow rapidly.
There is some evidence that certain treatments can help reduce the appearance of stretch marks.
Tretinoin cream has been shown to reduce the length and width of stretch marks, in one study reducing the length by 20 percent after 12 weeks of treatment (Source).
Tretinoin cream is most commonly used to treat acne, and should not be used by pregnant women or women who are trying to get pregnant, as it can cause congenital defects.
Laser therapy is the most effective way to treat stretch marks at any stage, from brand new ones to marks that have been there for years.
There are many different types of laser treatments, and your dermatologist can help determine which one is best for you and your skin type.