A scar is a mark that is left on the skin after a wound or an injury to the surface of the skin has healed.

Scars are very common. Most people have at least one scar on their body. They are a natural part of the healing process and can occur inside and outside the body.

Visible scars sometimes form after the skin has been broken. Scars can also occur on the internal organs – for example, where a cut has been made during surgery. Scars can also develop as a result of certain skin conditions, such as acne.

How do scars form?

When the skin is wounded and there is a break in the body’s tissues, the body produces more of a protein called collagen. Collagen builds up where the tissue is broken, helping to heal and close the wound.

For a period of months and years, new collagen continues to form and break down at the site of the wound. The scar gradually becomes smoother and softer.

Scars on the skin can take up to two years to fade. After this time it is unlikely that they will fade any more.

Read more about the causes of scars.

Stretch marks are types of scars that appear on the surface of the skin as a result of sudden growth, such as pregnancy or weight gain. See the Health A-Z topic about Stretch marks for more information.

Abnormal scars

Sometimes, abnormal scars develop. There are two types of abnormal scars:

• A hypertrophic scar is a red, raised scar that can form when there's excessive wound healing, for some reason.
• A keloid scar is an overgrowth of tissue that occurs when too much collagen is produced at the site of the wound and the scar keeps growing, even after the wound has healed.

Where do scars form?

Certain areas of the body are more likely to produce worse scars than others. Poor scars are more likely to form in the middle of the chest, the earlobe and the tip of the shoulder. These areas are also more prone to abnormal scars.

Scars that form on the knees and shoulders are often more visible because they need to move and stretch during the healing process. Also, different skin types form different types of scars.

Emotional effects

Scarring, particularly when it is on the face, can be very distressing. For some people, scarring can affect them a great deal. It may feel as if you are being stared at, and if you avoid meeting people as a result of your appearance, it can make you feel isolated. These feelings can lead to depression. If you if you feel that your scars are making you depressed or affecting your daily activities, visit your GP.

Outlook

A variety of different treatments can make scars less visible and improve their appearance. But the options available to you may depend on the type of scar that you have.

Be aware that scars never disappear completely, although most will gradually fade over a long period of time.

Over time, normal scars and hypertrophic scars will fade and become much paler. Keloid scars and more severe hypertrophic scars can be treated using:

• corticosteroid injections
• silicone gel sheets
• surgery
• pressure dressings

See Scars - treatment for more information.

Scars on the skin may appear when a cut or other injury is in the process of healing.

Normal scars

At first, a normal scar may be red and look sore, but it will usually fade as the injury begins to heal. If the skin at the edges of the wound has come together fairly neatly – for example, after a narrow injury or because the wound was stitched, the scar will usually heal as a thin, pale line.

In wider scars, where more surface skin is missing and more scar tissue is needed to join the gaps between the skin, such as in a bad graze on the knee, the scar may be darker and take longer to heal.

Normal scars are not usually painful. However, they can be dark and unsightly. When the scar tissue fades, it may be more noticeable if you have dark skin or when the rest of your skin tans and the scar remains pale.

Abnormal scars

Keloid scars

A keloid scar has the following characteristics:

• it pushes into the normal skin or hangs off the skin in a saggy lump
• it can feel itchy
• it can feel painful
• it can appear much larger than the original wound
• it can cause a burning sensation and feel tender to touch
• it can restrict movement if it is near joints and is particularly tight
• it is raised above the skin
• it is hairless and appears shiny
• it feels hard and has a ‘rubbery’ texture
• a newly formed keloid scar is red or purple, changing to a browner colour and becoming paler as it gets older

The areas of the body where keloid scars are more likely to form include:

• the area around the breastbone (sternum)
• the upper arms and shoulders (deltoids)
• the upper back

Hypertrophic scars

A hypertrophic scar has the following characteristics:

• it can restrict movement because scar tissue is not as flexible or sensitive as the original skin
• it heals within the size of the original wound
• the healing area is much thicker than usual; the skin will thicken for six months after the injury
• it is red and raised to begin with; over time, the scar will flatten and become much paler

Scarring is caused by the natural healing process when tissue in the body is broken. Breaks in the skin can be made in a number of ways, including:

• accidental injuries, such as cuts from falling off a bicycle
• deliberate harm from a weapon or from self-harm
• cuts made during surgery, such as a Caesarean section birth
• bites and scratches from animals or people
• burns and scalds from hot objects or liquids
• piercings, such as ear or nose piercings

Scarring can also be a symptom of certain health conditions, such as scleroderma, which affects the connective tissue and causes hardening of the skin. Connective tissue provides support and structure to other tissues and organs.

Scarring can also be a side effect or a complication of other conditions. For example, if you have a condition that causes a rash, such as chickenpox or acne, and you scratch the rash, you may be left with scars where the rash was.

It is thought that you have an increased risk of developing keloid scarring or hypertrophic scarring if a member of your family has previously had these types of scars. This is because this type of scarring appears to run in families.

Internal scarring can be caused by injuries or surgery.

Scars only need to be treated in the rare situation when they are painful or if a person is uncomfortable about how their scar looks.

Although scars cannot be removed completely, they can often be made less visible. Your GP may refer you to a dermatologist or a plastic surgeon for treatment. Some of the treatment options are outlined below.

Corticosteroid injections

Corticosteroid injections are used to prevent and treat some keloid and hypertrophic scars.

Corticosteroids are injected into the scar to reduce any inflammation (swelling) and to flatten the scar. Depending on the type of scar, the corticosteroid injection may need to be repeated. Two or three injections are usually given a month apart, although this type of treatment may continue for six months or possibly longer, depending on how the scar reacts to the injections.  

A local anaesthetic may be combined with the corticosteroid to reduce any pain and discomfort.

Silicon gel sheets

Silicon gel sheets are available from some pharmacies. They are used on healing skin (not open wounds) and can help to treat and prevent hypertrophic and keloid scars.

To be effective, silicon gel sheets should be worn over the scar 12 to 24 hours a day, for two to three months. Most sheets can be reused until they dissolve. Both the scar and the silicone sheet should be washed with mild soap and water each day.

Silicone is also available as an ointment, which can be applied to your skin to help treat scars.

You can ask your GP, dermatologist or pharmacist for further advice about using silicone gel sheets.

Surgery

Sometimes, surgery can improve the appearance of scars. Surgery can be used to:

• change the positioning of the scar
• change the shape of the scar
• release a tight scar that is close to a joint in order to improve movement

Be aware that having surgery on your scar will leave a new scar that will take up to two years to heal. There is also an increased risk of further keloid and hypertrophic scarring following surgery. After surgery, the recurrence rate for keloid scarring is 50-80%.

Pressure dressings

The aim of pressure dressings is to make scars less visible, and to flatten and soften them.

Pressure dressings are usually made from a stretchy, elastic material. They are worn over the scar 24 hours a day, for around 6 to12 months. They can also be used in combination with silicone gel sheeting to improve the appearance of scars over a long period of time.

Other treatments

A number of other treatment methods can help to reduce the appearance of scars. These include:

• medication
• make-up

These are briefly discussed below.

Medication

Dermatologists may prescribe medication, such as potassium aminobenzoate, to help break down scar tissue. Medication is often used to treat conditions such as scleroderma, which can cause extensive scarring and hardening of the skin.

Make-up

Make-up can help cover up scars and can be particularly useful for facial scars. Camouflage make-up that is specially designed for covering up scars is available over the counter at pharmacies.

It is not always possible to prevent scars from forming, but there are things that you or a healthcare professional can do to help your scar be less visible and heal better. For example:

• dirt and objects, such as glass or gravel, should be immediately cleaned out of a wound
• dead tissue should be cleared out of a wound to reduce the chance of infection
• if stitches are needed, the finest stitching material that can hold the wound together should be used

Other ways to prevent scarring include:

• using silicon gel sheets and pressure garment therapy to help prevent severe scarring
• avoiding scratching or picking at scabs and spots – this will help to prevent scarring

Last year Nicola, an office administrator from Newcastle, was involved in a bad road accident that caused serious injuries to her face. Her four-year-old daughter escaped with a broken collarbone.

Nicola needed 158 stitches in hospital. And as she was eight months pregnant, she couldn't have any anaesthetic to ease the considerable pain.

She said: "I had to grin and bear it – I still haven't really recovered even now. I felt really devastated when I realised that I would have a scar 8 inches across one side of my face. One part is really bad, where the skin is more jagged than the rest."

Fortunately, the young mother gave birth to a healthy boy a month later. However, she was still upset by the prominent scar across her face. Nicola visited her doctor, who referred her to the Red Cross’s skin camouflage service.

At the clinic, a Red Cross volunteer spent an hour showing Nicola how to use the camouflage creams, designed to cover disfiguring skin conditions.

Nicola remembered: "I just wanted to give it a try. I hadn't heard of anything I could use – normal make-up didn't hide the scar. After finding the right shade, the volunteer applied the cream for me. She then cleaned it off and I had to put it on myself, while she checked that I was doing it right. I was soon able to do it at home quite easily.

"I apply it every morning now before work – it takes five to 10 minutes to apply. It definitely makes me feel more confident than I did before. I'm looking forward to having an operation soon to correct the worst part of the scar, but when I go out the make-up is really good for hiding it. When I have the make-up on and pull my hair over that side of my face, you almost can't see it at all!"