Stretch marks
Introduction
Stretch marks are narrow, streak-like lines that can develop on the surface of the skin. They are also sometimes known as stria or striae.
Stretch marks are often red or purple at first, before gradually fading to a silvery-white colour. They are usually 1-10mm wide and are a few centimetres long.
The structure of the skin
The skin is made up of three main layers which are described below.
- The epidermis is the outer layer of skin that forms a protective barrier for the inside of your body and is made up of layers of flat cells.
- The dermis is the strong, supportive middle layer of skin that gives the skin its firmness and flexibility.
- The subcutis is also sometimes known as the hypodermis, is the inner layer of skin, consisting of fat and connective tissue.
Stretch marks occur in the middle layer of skin (dermis) when the skin is stretched considerably over a short period of time. This rapid stretching causes the dermis to break in places and allow the deeper layers of the skin to show through, forming stretch marks.
How common are stretch marks?
Anyone can get stretch marks and they are very common, although they tend to occur more often in women than in men. The areas of the body that are most commonly affected by stretch marks are the abdomen (tummy), the buttocks, and the thighs.
Stretch marks can appear on the skin whenever it is stretched as a result of sudden growth. For example they can appear:
- during pregnancy
- as a result of weight gain
- as a result of growth spurts during puberty, when the body matures sexually and the reproductive organs become functional
About 9 out of 10 women are affected by stretch marks during pregnancy. Around 7 out of 10 females and 4 out of 10 males develop stretch marks during puberty.
In some cases, stretch marks can also be a symptom of an underlying health condition, such as Cushing's syndrome.
See Stretch marks - causes for more information about this condition.
Outlook
Stretch marks are not harmful. They do not cause any significant medical problems and there is no specific medical treatment for them. As a result, there is usually no need to see your GP about them.
Over time, the skin will contract (shrink) and the stretch marks will turn into white-coloured scars that are lighter in colour and less obvious. However, they do not usually fade completely.
Some people who have stretch marks find them distressing. If you are concerned or distressed about your stretch marks, discuss possible treatment options with your GP, such as laser therapy or cosmetic surgery.
However, there is no guarantee that these treatments will work for you and there is a lack of evidence that they are effective in treating stretch marks. See Stretch marks - treatment for more information.
Although there is no way to cure stretch marks completely, you can do a number of things to reduce your risk of developing them, such as looking after your skin and controlling your weight. See Stretch marks - prevention for more information and advice.
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Symptoms
Stretch marks do not affect everyone and some people will not get them. It depends on your skin type. If your skin is more elastic, you are less likely to get stretch marks. If your skin contains a lower amount of collagen (a type of protein that keeps the skin stretchy), you are more likely to get stretch marks.
Stretch marks
An early sign of stretch marks is when the area of affected skin becomes thin, flattened and pink. Initially, the area may also feel itchy.
Stretch marks first appear as red or purple streaks or lines (striae rubra) on the surface of your skin. They are slightly raised to the touch and may feel wrinkly. Depending on the colour of your skin, they may also look pink, reddish brown or dark brown.
The lines will appear purple or pink in colour, before slowly flattening out. As the lines get flatter they begin to fade and usually change to a white colour (striae alba).
If you have stretch marks, they may appear in patches of parallel lines on your body. Your skin over the stretch marks may look thin and silvery, and can often look scar-like.
In many cases, stretch marks fade and become less noticeable over time, but this can take years.
Where do stretch marks appear?
You may develop stretch marks anywhere on your body where your skin has been stretched. However, they usually occur on the parts of your body where fat is stored, such as your:
- abdomen (tummy)
- buttocks
- thighs
- upper arms
- breasts (in women)
- shoulders of bodybuilders
Stretch marks that are caused by using corticosteroid treatments and by Cushing’s syndrome tend to be wider and larger and can also appear on the face.
See Stretch marks - causes for more information about corticosteroid treatments and Cushing’s syndrome.
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Causes
Stretch marks appear when your skin is stretched suddenly. They occur in the strong middle layer of your skin (the dermis), which supports your skin's outer surface (the epidermis).
The dermis is made up of strong fibres that connect to each other and allow your skin to stretch as your body grows. However, if a part of your body grows rapidly over a short period of time, the fibres can become thin and over-stretched and some of them may break.
Where the fibres in the dermis break, tiny tears develop and the blood vessels that lie under your skin show through. This is why stretch marks look reddish in colour when they first appear. Eventually, the blood vessels contract (shrink) to leave only the fat under your skin visible, and the stretch marks fade to a silvery white or grey colour.
Not everyone gets stretch marks. It may be that some people are more likely to develop stretch marks than others because their bodies produce a larger amount of a hormone called cortisol. Cortisol decreases the amount of collagen in your skin, which is a protein in the skin fibres that help to keep it stretchy.
The main causes of stretch marks include:
- pregnancy
- rapid weight gain
- puberty
- family history of stretch marks
- certain medications
- certain health conditions
These are outlined below.
Pregnancy
If you are pregnant, it is likely that you will develop stretch marks, particularly after the sixth month (second trimester) of your pregnancy.
Hormones that are produced by your body during pregnancy help to soften the ligaments (strong bands of tissue connecting joints) in your pelvis, so that they are more flexible when you come to deliver your baby. However, these hormones also soften the fibres in your skin, making you prone to stretch marks.
As your baby grows, you may develop stretch marks on your abdomen (tummy) as your skin is gradually stretched further and further. Stretch marks may also appear on your thighs and your breasts as they get bigger and heavier.
Over time, most stretch marks will fade to lines that are pale or flesh-coloured after childbirth.
Gaining weight quickly
You may get stretch marks if you put on a lot of weight over a short period of time. The stretch marks may remain even if you lose the weight that you have gained. However, they should fade over time.
If you diet regularly, stretch marks can form as your weight goes up and down rapidly. If you are dieting, it is important to lose weight slowly and steadily so that your skin is not put under strain.
Bodybuilders and athletes may also get stretch marks as their muscles increase in size.
Puberty
During puberty (the change from childhood to adulthood), the body tends to develop very quickly in growth spurts. As a result, males often get stretch marks on their shoulders and back, whereas females tend to get them on their hips, thighs and breasts.
See the Health topic about Puberty for more information.
Family history
If you have close relatives who have stretch marks (such as your mother), you may be more likely to develop them yourself. Stretch marks may affect both male and female members of your family, although they are more likely to occur in women.
Corticosteroids
You may develop stretch marks if you use corticosteroid medicines, such as creams, lotions or tablets for eczema (a skin condition that causes itching and redness).
Corticosteroids work in a similar way to the hormone cortisol, which is produced naturally in your body. Medicines that contain corticosteroids can ease the inflammation that is caused by skin conditions, but they can also decrease the amount of collagen that is in your skin.
Collagen is a type of protein that is needed to keep your skin stretchy, so the less collagen there is in your skin, the more likely it is that stretch marks will develop.
See the Health topic about Corticosteroids for more information.
Certain health conditions
Sometimes, stretch marks can be caused by a rare underlying health condition, such as Cushing's syndrome or Marfan syndrome.
Cushing's syndrome
Cushing's syndrome occurs when the body produces an excess amount of cortisol, the same hormone that may make some people more prone to stretch marks than others.
In Cushing's syndrome, your body produces so much cortisol that it can cause a variety of symptoms including:
- weight gain
- back pain
- excessive body and facial hair
If you have Cushing's syndrome, your stretch marks may be noticeable and dark in colour.
See the Health topic on Cushing’s syndrome for more information.
Marfan syndrome
Marfan syndrome is caused by a faulty gene that affects your body's connective tissues, including your skin. It weakens your body's tissues and affects their elasticity (ability to stretch), so that your skin is not as resistant to stretch marks as it should be.
If you have Marfan syndrome, you may have stretch marks on your shoulders, hips, or lower back. The condition also causes several other symptoms, such as curvature of the spine (scoliosis) and problems with vision.
See the Health topic about Marfan syndrome for more information.
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Diagnosis
Stretch marks are not harmful and there is usually no need to consult your GP about them.
However, if you feel that your stretch marks are unsightly and they are making you unhappy, it may be worth seeing your GP to discuss possible treatment options. However, there is no guarantee that any particular treatment that is recommended for you will work.
Before making any recommendations, your GP will examine your stretch marks, ask you about any other symptoms that you have, and whether or not you are taking any medicines.
Underlying health conditions
In rare cases, stretch marks can be a symptom of an underlying condition, such as Cushing's syndrome or Marfan syndrome.
You should see your GP if your stretch marks do not seem to be linked to changes in your weight or growth, or if you have any of the symptoms that are associated with either Cushing's syndrome, or Marfan syndrome (see Stretch marks - symptoms).
If your GP thinks that your stretch marks may be linked to another condition, they may need to carry out some tests. These may include blood or urine tests and imaging scans, such as an X-ray or a magnetic resonance imaging (MRI) scan. An MRI scan uses a strong magnetic field and radio waves to produce images of the inside of your body.
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Treatment
There is no specific medical treatment for stretch marks and, in most cases, there is no need to see your GP about them. Most stretch marks fade over time and are not particularly noticeable.
If you have a lot of stretch marks that affect a large part of your body, or if you are worried that they look unsightly, there may be treatments available.
However, there is little or no medical evidence to show that any of these treatments will work, so it is important that you are realistic about what they can achieve.
Creams, gels and lotions
There are many creams, gels and lotions that claim to be able to remove stretch marks. These products are essentially moisturisers for your skin and are available from pharmacies, supermarkets and health and beauty shops.
It is better to apply creams, gels and lotions to the stretch marks when they are at an early stage (striae rubra) and still purple. However, it is very doubtful that oils or creams can help prevent stretch marks.
Laser therapy
Laser therapy cannot remove stretch marks altogether, but it may help them to fade and appear less obvious.
There are several different types of laser therapy that may be used to treat stretch marks, such as pulsed dye laser treatment. This type of laser therapy works on early stretch marks (that are still red) by sealing the blood vessels within your skin and speeding up the fading process.
Laser therapy for stretch marks is not available on the NHS and is usually very expensive. It is likely that you will need many treatments in order to obtain visible results, but the exact number will depend on your skin colour and type.
Cosmetic surgery
Cosmetic surgery for stretch marks is a very expensive and is rarely recommended.
If you have stretch marks on your abdomen (tummy) as well as a large amount of loose skin, it may be possible to have an operation called an abdominoplasty, which is also known as a tummy tuck. An abdominoplasty can remove the excess fat and skin around your abdomen, as well as removing the stretch marks below your belly button at the same time.
As this type of surgery is a cosmetic procedure (used to improve your appearance), it is not available on the NHS. Cosmetic surgery also carries several risks, and it can cause considerable scarring.
See the Health topic about Cosmetic surgery for more information.
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Prevention
Stretch marks are very common and cannot be prevented altogether. However, the following advice may help you to reduce your risk of developing stretch marks.
Maintain a healthy weight
One of the most common causes of stretch marks is gaining weight in a short period of time.
Putting on a lot of weight and diets that cause your weight to change rapidly can cause stretch marks to form because your skin is literally stretched by the sudden growth. Therefore, avoiding rapid weight gain and weight loss can help prevent stretch marks from forming.
If you need to lose weight, do it slowly by ensuring that you get plenty of regular exercise and by eating a healthy, balanced diet. Do not lose more than 0.5 kg (1lb) a week.
To find out whether you are overweight or obese, use the Body mass index (BMI) calculator.
Look after your skin
Massaging your skin everyday with moisturiser or a massage glove can help to improve your circulation and encourage new tissue growth.
It is also important to eat a healthy, balanced diet that is rich in vitamins and minerals - particularly vitamins E and C and the minerals zinc and silicon. These vitamins and minerals help to keep your skin healthy.
See the Health topic about Diet for more information and advice.
During pregnancy
If you are pregnant, it is normal and healthy to put on a significant amount of weight in a short space of time, but it is a myth that you need to 'eat for two'.
You are more likely to get stretch marks during pregnancy due to hormonal changes that affect your skin. However, you may be able to minimise their appearance by gaining pregnancy weight steadily.
While you are pregnant, you need to take in approximately 2,500 calories a day. However, this is only 500 calories more than a woman's normal recommended calorie intake.
It is important that these calories come from a well-balanced diet that is rich in wholewheat carbohydrates, such as bread and pasta, as well as fruit and vegetables.
During pregnancy, your weight gain should be slow and gradual. The amount of weight you put on will depend on the weight you were before you became pregnant. It is normal to gain 1-2kg (2.2-4.4lb) over the first 12 weeks of your pregnancy.
As a rough guide, during pregnancy:
- Women who are underweight (have a BMI of less than 18.5) should gain 12.7-18.1kg (28-40lb).
- Women who are a normal weight (have a BMI of 18.5-24.9) should gain 11.3-15.9kg (25-35lb).
- Women who are overweight (have a BMI of more than 25) should gain 6.8-11.3kg (15-25lb).
- Women who are obese (have a BMI of more than 30) should gain 5-9.1kg (11-20lb).
Speak to your GP, midwife or health visitor if you are worried that you are not gaining weight at a healthy rate or if you are concerned about your stretch marks.
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