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 on their body. They are a natural part of the healing process.
Scars can occur inside and outside the body. For example, they can occur on the internal organs where a cut has been made during surgery, and can develop after certain skin conditions, such as acne and chicken pox.
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, as part of the healing process. Collagen builds up where the tissue has been damaged, helping to heal and strengthen the wound.
For a period of about three months or longer, new collagen continues to form and blood supply increases, causing the scar to become raised, lumpy and red. Some collagen then breaks down at the site of the wound, the blood supply reduces and the scar gradually becomes smoother, softer and paler.
Although scars are permanent, they can fade over a period of up to two years. It is unlikely they will fade any more after this time.
Skin wounds can be caused by many things, including:
burns and scalds
Where do scars form?
Scarring is unpredictable and varies from person to person. Certain areas of the body are more at risk of scarring, such as the chest, back, ear lobe and the shoulder.
Scars that form on the knees and shoulders can appear stretched or widened as a result of the healing process occurring over movable joints.
Types of scars
The different types of scars include:
Flat, pale scars – these are the most common type of scar and are due to the body's natural healing process. Initially, they may be red or dark and raised after the wound has healed, but will become paler and flatter naturally over time. This can take up to two years.
Hypertrophic scars – red, raised scars that form along a wound and can remain this way for a number of years.
Keloid scars – these are caused by an excess of scar tissue produced at the site of the wound, where the scar grows beyond the boundaries of the original wound, even after it has healed.
Pitted (atrophic or "ice-pick") scars – these have a sunken appearance.
Contracture scars – these arecaused by the skin shrinking and tightening, usually after a burn, which can restrict movement.
Depending on the type and age of a scar, a variety of different treatments may help make them less visible and improve their appearance.
Scars are unlikely to disappear completely, although most will gradually fade over time.
If scarring is unsightly, uncomfortable or restrictive, treatment options may include:
silicone gel sheets
cosmetic camouflage (make-up)
It is often the case that a combination of treatments can be used.
Emotional effects of scarring
Scarring, particularly when it is on the face, can be very distressing, especially if you feel you are being stared at. If you avoid meeting people as a result of your appearance, you may become socially isolated. This can lead to feelings of depression.
If you feel that your scars are making you depressed or affecting your daily activities, make sure you visit your GP.
Preventing or improving scars
It isn't possible to prevent scars from forming, but there are things you can do to help your scar be less visible and heal better, such as immediately cleaning dirt, objects and dead tissue from wounds.
Other ways to improve scarring include:
not scratching or picking at scabs and spots
covering wounds with a waterproof ointment (such as Vaseline)
using silicone gels or sheets to reduce redness and encourage healing
Types of scars
Scars on the skin may appear when a cut or other injury is in the process of healing. The different types of scars vary in appearance.
Flat, pale scars
The most common type of scar is the flat, pale scar that forms as a result of the body's natural healing process.
Initially, they may be red or dark and raised after the wound has healed, but will become paler and flatter naturally over time as the injury heals.
This process can take up to two years, and there will always be some visible evidence of the original wound.
If the skin at the edges of the wound has come together neatly, the scar will usually heal as a thin, pale line. In wider wounds, where more surface skin is missing and more scar tissue is needed to bridge the gap between the edges of damaged skin (such as a bad graze on the knee), the scar may be less neat and may take longer to heal.
These scars are not usually painful, although they may be itchy for a few months. They can also be quite dark in colour and unsightly.
If you have a darker skin type, scar tissue may fade to leave a brown or white mark. These are often permanent, but can sometimes improve over time. If your skin is tanned, the scar may appear more obvious, as scar tissue does not tan and remains pale.
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.
Keloid scars often have the following characteristics:
they are often raised above the skin
they can feel itchy
they can feel painful
they can appear much larger than the original wound
they can cause a burning sensation and feel tender to touch
they can restrict movement if they are tight and near a joint
they are raised above the skin
they are hairless and appears shiny
they feel hard and have a "rubbery" texture, although some keloids can form soft lumps (such as on the ear lobe after piercings)
a newly-formed keloid scar is red or purple, becoming paler with time
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
on the ear lobes
Like keloid scars, hypertrophic scars are the result of an imbalance in the production of collagen in a healing wound.
Unlike keloid scars, they do not extend beyond the boundary of the original wound, but may continue to thicken for up to six months.
A hypertrophic scar is a red, raised scar that forms along a wound and can have the following characteristics for around two to five years:
it can restrict movement because scar tissue is not as flexible as the original skin
it heals within the size of the original wound
the healing tissue is thicker than usual
it is red and raised initially, becoming flatter and paler with time
Hypertrophic scars can have this appearance for many years.
Pitted or sunken scars (atrophic or "ice-pick" scars)
Some scars caused by skin conditions such as acne and chickenpox can have a sunken or pitted appearance.
They can also be the result of an injury, which may have included the loss of underlying fat.
Scar contractures are commonly caused by burns. These occur when the skin “shrinks”, leading to tightness and a restriction in movement.
What are stretch marks?
Stretch marks are skin markings that can look similar to long thin scars, but they are actually formed in a different way.
Causes of scars
Scarring results from the body's natural healing process after body tissue has been damaged.
Tissue damage can occur for a number of reasons, 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
body piercings – such as ear or nose piercings
injections – such as vaccination against tuberculosis (BCG vaccination)
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, you may be left with scars where the rash was (this is more likely to happen if you scratch or pick at the affected areas).
It is thought that keloid scarring and hypertrophic scarring may run in families. This means 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.
Internal scarring can be caused by injuries or surgery.
People seek help for scars if they are painful or itchy, if they are unsightly, or if they restrict movement.
Although scars cannot be removed completely, they can often be made less visible. However, more research is required to assess the effectiveness of the different treatments.
Your GP may refer you to a dermatologist or a plastic surgeon for treatment.
Corticosteroid injections are used to treat some keloid and hypertrophic scars.
Multiple small injections are made into the scar to reduce any swelling (inflammation) and to flatten the scar. Depending on the type of scar, these may need to be repeated. Injections are usually given on three occasions, at four- to six-week intervals, to assess your body’s response. Treatment may sometimes continue for several months if the scar is improving.
This treatment cannot remove scars, but it can improve their appearance.
Silicone gels or sheets
Silicone gels or sheets are available from some pharmacies. They are used on healing skin (not open wounds) to reduce redness and to try to minimise hypertrophic or keloid scars.
To be effective, silicone gels or sheets should be placed over the scar for 12 hours a day, for at least three months.
You can ask your GP, dermatologist or pharmacist for more advice about a range of silicone-based scar treatments.
Surgery for scars
Surgery can sometimes improve the appearance of scars, as it can be used to:
change the positioning of the scar
change the width or shape of the scar
release a tight scar that is close to a joint, to improve movement
Be aware that having surgery on your scar will leave a new scar that will take up to two years to improve in appearance. If surgery is used to treat a hypertrophic scar, there is a risk that the scarring may be worse after the surgery.
Surgery alone is not advised for keloids, as they tend to grow back larger. Surgery for keloids is often combined with corticosteroid injections at the site of the removed scar immediately after surgery. Some plastic surgeons also add other treatments, such as X-ray therapy and oral antibiotics, to try to minimise the recurrence of a keloid that has been surgically treated. You can talk to your surgeon about this treatment.
Pressure dressings for scars
The aim of pressure dressings is to flatten and soften scars. They are most often used for large burn scars or after skin grafts.
Pressure dressings are usually made from a stretchy, elastic material. They are worn over the scar 24 hours a day, for around 6 to 12 months. They can also be used in combination with silicone gel sheeting, to improve the appearance of scars over a long period of time.
Pressure dressings are usually used under specialist supervision.
Make-up for scars
Cosmetic camouflage (make-up) can help cover up scars and can be particularly useful for facial scars. Some are waterproof and can stay in place for two or three days.
Camouflage make-up that is specially designed for covering up scars is available over the counter at pharmacies. You can also ask your GP for advice.
Please note that camouflage colour testing (to get a good colour match for your skin type) can be a lengthy process, sometimes taking over an hour, and needs to be performed by someone who is qualified.
Laser or light therapy (pulses of light) can reduce the redness in a scar by targeting the blood vessels in the excess scar tissue. For some pitted scars, laser surgery (laser re-surfacing) is used to try to make the scar flatter. This involves using a laser to remove the top layers of skin, which stimulates collagen production in the deeper layers.
However, there are very few long-term studies to prove the effectiveness and safety of this therapy. If you have laser therapy, it's important to make sure that the person carrying it out is a fully trained medical practitioner with experience in improving scars.
Dermal fillers are injections (often of a man-made acid) used to "plump up" pitted scars. Treatments can be costly and the results are usually temporary. Repeat treatments are needed to maintain the effect.
Skin needling, which involves rolling a small device covered in hundreds of tiny needles across the skin, is also reported to be helpful, but repeat treatments are often needed to achieve an effect, and results vary considerably.
Low-dose, superficial radiotherapy may reduce the recurrence rate of hypertrophic and keloid scars after surgery. It is effective in about 70% of cases but, because of the possibility of long-term side effects, it is only reserved for the most serious cases.
Scars and skin creams
Although Vitamin E cream is sometimes recommended for the self-management of scars, there is no medical evidence to suggest that it has an effect.
However, the massaging of a moisturiser such as E45 into the scar will keep it from becoming dry and help make it supple.
Scars may be sensitive to the sun. Sunscreen can be used to protect them.
Scarring can affect a person both physically and psychologically. There are a number of support groups and organisations that provide help and advice to people who are living with scarring.
Support organisations include:
British Association of Skin Camouflage
The Scar Information Service
Children’s Burns Club