Scars are areas of fibrous tissue (fibrosis
Fibrosis is the formation of excess fibrous connective tissue in an organ or tissue in a reparative or reactive process. This is as opposed to formation of fibrous tissue as a normal constituent of an organ or tissue...

) that replace normal skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...

 after injury. A scar results from the biological process of wound
A wound is a type of injury in which skin is torn, cut or punctured , or where blunt force trauma causes a contusion . In pathology, it specifically refers to a sharp injury which damages the dermis of the skin.-Open:...

 repair in the skin and other tissues
Biological tissue
Tissue is a cellular organizational level intermediate between cells and a complete organism. A tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function. These are called tissues because of their identical functioning...

 of the body. Thus, scarring is a natural part of the healing
Physiological healing is the restoration of damaged living tissue, organs and biological system to normal function. It is the process by which the cells in the body regenerate and repair to reduce the size of a damaged or necrotic area....

 process. With the exception of very minor lesion
A lesion is any abnormality in the tissue of an organism , usually caused by disease or trauma. Lesion is derived from the Latin word laesio which means injury.- Types :...

s, every wound (e.g. after accident
An accident or mishap is an unforeseen and unplanned event or circumstance, often with lack of intention or necessity. It implies a generally negative outcome which may have been avoided or prevented had circumstances leading up to the accident been recognized, and acted upon, prior to its...

, disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...

, or surgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...

) results in some degree of scarring. An exception to this is animals with regeneration
Regeneration (biology)
In biology, regeneration is the process of renewal, restoration, and growth that makes genomes, cells, organs, organisms, and ecosystems resilient to natural fluctuations or events that cause disturbance or damage. Every species is capable of regeneration, from bacteria to humans. At its most...

, which do not form scars and the tissue will grow back exactly as before.

Sherratt et al, explain that scar tissue is the same protein (collagen) as the tissue that it replaces, but the fiber composition of the protein is different; he explains that instead of a random basketweave formation of the collagen fibers found in normal tissue, in fibrosis the collagen cross-links and forms a pronounced alignment in a single direction. This collagen scar tissue alignment is usually of inferior functional quality to the normal collagen randomised alignment. For example, scars in the skin are less resistant to ultraviolet radiation, and sweat gland
Sweat gland
Sweat glands, or sudoriferous glands, are small tubular structures of the skin that produce sweat. There are two kinds of sweat glands:...

s and hair follicle
Hair follicle
A hair follicle is a skin organ that produces hair. Hair production occurs in phases, including a growth phase , and cessation phase , and a rest phase . Stem cells are principally responsible for the production of hair....

s do not grow back within scar tissue. A myocardial infarction
Myocardial infarction
Myocardial infarction or acute myocardial infarction , commonly known as a heart attack, results from the interruption of blood supply to a part of the heart, causing heart cells to die...

, commonly known as a heart attack, causes scar formation
Myocardial scarring
Myocardial scarring is fibrous tissue that replaces normal tissue destroyed by injury or disease pertaining to the muscular tissue of the heart....

 in the heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...

 muscle, which leads to loss of muscular power and possibly heart failure. However, there are some tissues (e.g. bone
Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...

) that can heal without any structural or functional deterioration.


First attested in English in late 14th century, the word scar derives from Old French
Old French
Old French was the Romance dialect continuum spoken in territories that span roughly the northern half of modern France and parts of modern Belgium and Switzerland from the 9th century to the 14th century...

 escharre, from Late Latin
Late Latin
Late Latin is the scholarly name for the written Latin of Late Antiquity. The English dictionary definition of Late Latin dates this period from the 3rd to the 6th centuries AD extending in Spain to the 7th. This somewhat ambiguously defined period fits between Classical Latin and Medieval Latin...

 eschara, which is the latinisation
Latinisation (literature)
Latinisation is the practice of rendering a non-Latin name in a Latin style. It is commonly met with for historical personal names, with toponyms, or for the standard binomial nomenclature of the life sciences. It goes further than Romanisation, which is the writing of a word in the Latin alphabet...

 of the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 ἐσχάρα (eskhara), meaning "hearth, fire-place", but in medicine "scab, eschar on a wound caused by burning or otherwise".


There are several different kinds of scarring, each caused by differing amounts of collagen over expression. One of the most common types is hypertrophic and keloid
A keloid is a type of scar, which depending on its maturity, is composed mainly of either type III or type I collagen. It is a result of an overgrowth of granulation tissue at the site of a healed skin injury which is then slowly replaced by collagen type 1...

 scarring, both of which experience excessive stiff collagen bundled growth over extending the tissue, blocking off regeneration of tissues. Another form is atrophic scarring (sunken scarring), which also has an over expression of collagen blocking of regeneration, this scar type is sunken, the collagen bundles do not over extend the tissue. Stretch marks (striae) are regarded as scars to some.


Hypertrophic scars occur when the body overproduces collagen, which causes the scar to be raised above the surrounding skin. Hypertrophic scars take the form of a red raised lump on the skin.


A keloid is a type of scar, which depending on its maturity, is composed mainly of either type III or type I collagen. It is a result of an overgrowth of granulation tissue at the site of a healed skin injury which is then slowly replaced by collagen type 1...

 scars are a more serious form of scarring, because they can carry on growing indefinitely into a large, tumorous (although benign) neoplasm.

Hypertrophic scars are often distinguished from keloid scars by their lack of growth outside the original wound area, but this commonly taught distinction can lead to confusion. All keloid scars are hypertrophic but "only a small percentage of large scars" are keloid. Phenotypic differences exist between keloid scars and hypertrophic scars. Keloid scars can occur on anyone, but they are most common in dark-skinned people. Keloid scars can be caused by surgery, an accident, by acne
Acne vulgaris
Acne vulgaris is a common human skin disease, characterized by areas of skin with seborrhea , comedones , papules , pustules , Nodules and possibly scarring...

 or, sometimes, from body piercings. In some people, keloid scars form spontaneously. Although they can be a cosmetic problem, keloid scars are only inert masses of collagen and therefore completely harmless and non-cancerous. However, they can be itchy or painful in some individuals. They tend to be most common on the shoulder
The human shoulder is made up of three bones: the clavicle , the scapula , and the humerus as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder make up the shoulder joints. The major joint of the shoulder is the glenohumeral joint, which...

s and chest
The chest is a part of the anatomy of humans and various other animals. It is sometimes referred to as the thorax or the bosom.-Chest anatomy - Humans and other hominids:...

. Hypertrophic scars and its subset Keloid tend to be more common in wounds closed by secondary intention.


An atrophic scar takes the form of a sunken recess in the skin, which has a pitted appearance. These are caused when underlying structures supporting the skin, such as fat
Fats consist of a wide group of compounds that are generally soluble in organic solvents and generally insoluble in water. Chemically, fats are triglycerides, triesters of glycerol and any of several fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure...

 or muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...

, are lost. This type of scarring is often associated with acne, chickenpox
Chickenpox or chicken pox is a highly contagious illness caused by primary infection with varicella zoster virus . It usually starts with vesicular skin rash mainly on the body and head rather than at the periphery and becomes itchy, raw pockmarks, which mostly heal without scarring...

, other diseases (especially staphylococcus [or MRSA] infection), surgery or accidents.

Stretch marks

Stretch marks (technically called striae) are also a form of scarring. These are caused when the skin is stretched rapidly (for instance during pregnancy
Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...

, significant weight gain or adolescent growth spurts), or when skin is put under tension during the healing process, (usually near joints). This type of scar usually improves in appearance after a few years.

Elevated corticosteroid
Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex. Corticosteroids are involved in a wide range of physiologic systems such as stress response, immune response and regulation of inflammation, carbohydrate metabolism, protein catabolism, blood electrolyte...

 levels are implicated in striae development.


If a wound re-epithelizes within two weeks there will be minimal collagen deposited and there will be no scar. And generally if a wound takes longer than three to four weeks to re-epithelize a scar forms.

The scar is a result of the body's repair mechanism after injury on many tissues.

Any injury does not become a scar until the wound has completely healed; this can take many months, or years in the worst pathological cases like keloids. To begin to patch the defect a clot is created; the clot is the beginning process that results in a provisional matrix. In the process the first layer is a provisional matrix and is not scar. Over time the wounded body tissue then over-expresses collagen inside the provisional matrix to create a collagen matrix. This collagen over expression continues and cross-links the fiber arrangement inside the collagen matrix, making the collagen dense. This densely-packed collagen, morphing into an inelastic whitish collagen scar wall, blocks off cell communication and regeneration and as a result, the new tissue that is generated will have a different texture and quality than the surrounding non-wounded tissue. This prolonged collagen-producing process results in a fortuna scar.

The scarring is created by fibroblast proliferation, a process that begins with a reaction to the clot.

To mend the damage, fibroblasts slowly form the collagen scar. The fibroblast proliferation is circular and cyclically, the fibroblast proliferation lays down thick whitish collagen
Collagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content...

 inside the provisional and collagen matrix, resulting in the packed abundant production of collagen
Collagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content...

 on the fibers giving scars their uneven texture. Over time, the fibroblasts continue to crawl around the matrix, adjusting more fibers and, in the process, the scarring settles and becomes stiff. This fibroblast proliferation also contracts the tissue. In non-wounded tissue, these fibers are not over expressed with thick collagen and do not contract.

The fibroblast involved in scarring and contraction is the myofibroblast
A Myofibroblast is a cell that is in between a fibroblast and a smooth muscle cell in differentiation.-Developmental origin:There are many possible ways of myofibroblast development:#Partial smooth muscle differentiation of a fibroblastic cell...

. The myofibroblast is a specialized contractile fibroblast and these cells express a a-smooth muscle actin (a-SMA).

The myofibroblast are absent in the first trimester in the embryonic stage which heals scar free; in small incisional or excision wounds less than 2mm that also heal without scarring; and in adult non wounded tissues were the fibroblast in itself is arrested ; however the myofibroblast is found massively in adult wound healing which heals with scar.

The myofibroblasts make up a big proportion of the fibroblasts proliferating in the post embryonic wound at the onset of healing. In the rat model for instance the myofibroblast can be up to 70% of the fibroblasts. and is responsible for fibrosis on tissue
Generally the myofibroblast disappear from the wound within 30 days; but can stay around in pathological cases in hypertrophy like keloids.

As well as the fibroblast
A fibroblast is a type of cell that synthesizes the extracellular matrix and collagen, the structural framework for animal tissues, and plays a critical role in wound healing...

 proliferation there is prolonged inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...


Redness that often follows an injury to the skin is not a scar, and is generally not permanent (see wound healing
Wound healing
Wound healing, or cicatrisation, is an intricate process in which the skin repairs itself after injury. In normal skin, the epidermis and dermis exists in a steady-state equilibrium, forming a protective barrier against the external environment...

). The time it takes for this redness to dissipate may, however, range from a few days to, in some serious and rare cases, a few years.

Scars form differently based on the location of the injury on the body and the age of the person who was injured.

The worse the initial damage is, the worse the scar will generally be.

Skin Scars: Skin scars occur when the dermis
The dermis is a layer of skin between the epidermis and subcutaneous tissues, and is composed of two layers, the papillary and reticular dermis...

 (the deep, thick layer of skin) is damaged. Most skin scars are flat and leave a trace of the original injury
-By cause:*Traumatic injury, a body wound or shock produced by sudden physical injury, as from violence or accident*Other injuries from external physical causes, such as radiation injury, burn injury or frostbite*Injury from infection...

 that caused them.

Wounds that heal by secondary intention tend to scar worse than wounds closed by primary intention.


Early and effective treatment of acne scarring can prevent severe acne and the scarring that often follows High melanin levels and either African or Asian ancestry may make adverse scarring more noticeable. no prescription drugs for the treatment or prevention of scars were available.

Chemical peels

Chemical peels are chemicals which destroy the epidermis in a controlled manner, leading to exfoliation and the alleviation of certain skin conditions including superficial acne scars. Various chemicals can be used depending upon the depth of the peel and caution should be used, particularly for dark-skinned individuals and also including individuals susceptible to keloid formation or those with active infections.

Filler injections

Filler injections of Collagen
Collagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content...

 or ArteFill
Artefill is a non-resorbable injectable dermal filler for the correction of wrinkles and lines on the face. Artefill is approved by the U.S. Food and Drug Administration for correctıng smile lines but it is widely used "off label" by physicıans to fill lines and wrinkles all over the face...

 can be used to raise atrophic scars to the level of surrounding skin. Risks vary based upon the filler used, and can include temporary improvement, further disfigurement, and allergic reaction.


Dermabrasion is a surgical procedure that involves the controlled abrasion of the upper layers of the skin with sandpaper or other mechanical means. Nowadays it has become common to use CO2 or Erbium:YAG laser as well. The procedure requires a local anaesthetic...

 involves the removal of the surface of the skin with specialist equipment and usually involves a local anaesthetic.

Laser Treatment

Non-ablative lasers such as the 585 nm Pulsed dye laser, 1064 nm and 1320 nm Nd:YAG, or the 1540 nm Er:Glass are used as the standard laser therapy for hypertrophic scars and keloids. This therapy smooths the skin by heating up and redistributing collagen while avoiding damage to the epidermis via contact cooling. Multiple sessions are usually required for a significant reduction in redness and improvement in the texture and pliability of hypertrophic scars and keloids.

Ablative lasers such as the carbon dioxide laser
Carbon dioxide laser
The carbon dioxide laser was one of the earliest gas lasers to be developed , and is still one of the most useful. Carbon dioxide lasers are the highest-power continuous wave lasers that are currently available...

 or Er:YAG offer the best results for atrophic and acne scars. Like dermabrasion
Dermabrasion is a surgical procedure that involves the controlled abrasion of the upper layers of the skin with sandpaper or other mechanical means. Nowadays it has become common to use CO2 or Erbium:YAG laser as well. The procedure requires a local anaesthetic...

, ablative lasers work by destroying the epidermis to a certain depth. Healing times for ablative therapy are much longer and the risk profile is greater compared to non-ablative therapy; however, non-ablative therapy offers only minor improvements in cosmetic appearance of atrophic and acne scars.


Low-dose, superficial radiotherapy is sometimes used to prevent recurrence of severe keloid and hypertrophic scarring. It is thought to be effective despite a lack of clinical trials, but only used in extreme cases due to the perceived risk of long-term side effects.

Semiocclusive Ointments & Pressure dressing

Silicone scar treatments
Silicone scar sheet
Silicone scar sheets are a type of treatment used to prevent the formation of new scars and to reduce the appearance of existing scars. The scar sheet is lined on one side with silicone gel. The other side is often lined with a smooth fabric or a transparent film...

 are commonly used in preventing scar formation and improving existing scar appearance. The effectiveness and safety of silicone sheeting for the treatment and prevention of scars is supported by an abundance of clinical studies.

There have been more controlled clinical trials performed on the treatment of scars using Silicone Gel Sheeting than most other methods.1

“the treated scars were improved significantly at 4, 8, and 12 weeks, compared with both their own treatment value and the control scars”2
“We conclude that this simple method of treating hypertrophic scar is efficacious, even in relatively chronic cases.”2
“Keloids and hypertrophic scars in children are effectively treated with silicone gel sheeting.”3
“Topical silicone gel sheeting is an effective method for the treatment of hypertrophic and keloid scars.” 4
For treatment of scars, “First-line therapy is silicone sheeting”5

Silicone gel sheeting is the only non-invasive option for which evidence-based recommendations have been made for both scar treatment and prevention.

“Overall, the success rate (somewhat improved to greatly improved) for the treatment of hypertrophic and keloid scars is high (95%).”6

1. Mustoe TA, Cooter RD, Gold MH, et al. International Clinical Recommendations on scar management. Plast Reconstr Surg 2002;110:560-71

2. Ahn ST, Monafo W, Mustoe TA Surgery 1989 Oct, 106 4:781-786

3. Laude TA ;Current Opinion Pediatrics, 1996 Aug 8 4: 381-385

4. Gold MH / Journal of Dermatology - Surgical Oncology Topical Silicone Gel Sheeting in the Treatment of Hypertrophic Scars and Keloids:A Dermatological Experience 1993; 19:912-916

5. Tønseth KA, Tindholdt TT, Solberg US, Busic V, Mesic H, Begic A Tidsskr Nor Laegeforen. 2003 Nov 6;123(21):3033-5

6. Dockery GL, Nilson RZ. Journal of Foot and Ankle Surgery 1994 Mar-Apr; 33 2:110 Treatment of Hypertrophic and Keloid Scars with Silastic Gel Sheeting
Semiocclusive silicone based ointments are used to speed healing and reduce the appearance of scars and likely work in a similar manner as silicone scar sheets.

Pressure dressings are commonly used in managing burn and hypertrophic scars, although supporting evidence is lacking. These involve elastic
An elastomer is a polymer with the property of viscoelasticity , generally having notably low Young's modulus and high yield strain compared with other materials. The term, which is derived from elastic polymer, is often used interchangeably with the term rubber, although the latter is preferred...

 materials or gauze which apply pressure to the area. For large scars and particularly large burn
Burn (injury)
A burn is a type of injury to flesh caused by heat, electricity, chemicals, light, radiation or friction. Most burns affect only the skin . Rarely, deeper tissues, such as muscle, bone, and blood vessels can also be injured...

s, pressure garments may be worn. It is believed that they work by applying constant pressure to surface blood vessels and eventually causing scars to flatten and become softer. Retrospective and ultrasonic studies since the 1960s have supported their use, but the only randomized clinical trial found no statistically significant difference in wound healing. Care providers commonly report improvements, however, and pressure therapy has been effective in treating ear keloids. The general acceptance of the treatment as effective may prevent it from being further studied in clinical trials.


A long term course of steroid
A steroid is a type of organic compound that contains a characteristic arrangement of four cycloalkane rings that are joined to each other. Examples of steroids include the dietary fat cholesterol, the sex hormones estradiol and testosterone, and the anti-inflammatory drug dexamethasone.The core...

 injections under medical supervision, into the scar may help flatten and soften the appearance of keloid or hypertrophic scars.

The steroid is injected into the scar itself; since very little is absorbed into the blood stream, side effects of this treatment are minor. However, it does cause thinning of the scar tissue so it does carry risks when injected into scars caused by operations into ruptured tendons. This treatment is repeated at 4-6 week intervals.

Topical steroids are ineffective.


Scar revision is a process of cutting the scar tissue out. After the excision, the new wound is usually closed up in order to heal by primary intention, instead of secondary intention. Deeper cuts need a multi-layered closure to heal optimally, otherwise depressed or dented scars can result.

Surgical excision of hypertrophic or keloid scars is often associated to other methods such as pressotherapy or silicone gel sheeting. Lone excision of keloid scars however shows a high recurrence rate close to 45%. A clinical study is currently ongoing to assess the benefits of a treatment combining surgery and laser-assisted healing in hypertrophic or keloid scars.


Research shows the use of vitamin E
Vitamin E
Vitamin E is used to refer to a group of fat-soluble compounds that include both tocopherols and tocotrienols. There are many different forms of vitamin E, of which γ-tocopherol is the most common in the North American diet. γ-Tocopherol can be found in corn oil, soybean oil, margarine and dressings...

 and onion extract (sold under Mederma
Mederma is a topical product used to improve scar appearance. It is a gel based on an onion extract and produced by Merz Pharmaceuticals of Frankfurt, Germany. Mederma's marketing claims it can make scars "softer, smoother, and less noticeable"...

) as treatments for scars is ineffective. Vitamin E causes contact dermatitis
-Etymology:Dermatitis derives from Greek derma "skin" + -itis "inflammation" and genetic disorder.-Terminology:There are several different types of dermatitis. The different kinds usually have in common an allergic reaction to specific allergens. The term may describe eczema, which is also called...

 in up to 33% of users and in some cases it may worsen scar appearance. Vitamin C and some of its esters also fade the dark pigment associated with some scars.

Intentional scarring

The permanence of scarring has led to its intentional use as a form of body art
Body art
Body art is art made on, with, or consisting of, the human body. The most common forms of body art are tattoos and body piercings, but other types include scarification, branding, scalpelling, shaping , full body tattoo and body painting.More extreme body art can involve things such as mutilation...

 within some cultures and subcultures (see scarification
Scarifying involves scratching, etching, burning, or superficially cutting designs, pictures, or words into the skin as a permanent body modification.In the process of body scarification, scars are formed by cutting or branding the skin...

). These forms of ritual and non-ritual scarring practices can be found in many groups and cultures around the world.


An intradermal injection of Transforming Growth Factor Beta 3 (TGFβ3) is being tested. The results of three trials already completed were published in the Lancet along with an editorial commentary.

A study implicated the protein Ribosomal s6 kinase
Ribosomal s6 kinase
In molecular biology, ribosomal s6 kinase is a family of protein kinases involved in signal transduction. There are two subfamilies of rsk, p90rsk, also known as MAPK-activated protein kinase-1 , and p70rsk, also known as S6-H1 Kinase or simply S6 Kinase. There are three variants of p90rsk in...

 (RSK) in the formation of scar tissue and found that the introduction of a chemical to counteract RSK could halt the formation of Cirrhosis
Cirrhosis is a consequence of chronic liver disease characterized by replacement of liver tissue by fibrosis, scar tissue and regenerative nodules , leading to loss of liver function...

. This treatment also has the potential to reduce or even prevent altogether other types of scarring.

Research has also implicated osteopontin
Osteopontin , also known as bone sialoprotein I , early T-lymphocyte activation , secreted phosphoprotein 1 , 2ar and Rickettsia resistance , is a human gene product, which is also conserved in other species...

 in scarring.

A research group in South Africa has a combination approach using a microporous tape in addition to Bulbine frutescens
Bulbine frutescens
Bulbine frutescens is a species of flowering plant in the genus Bulbine....

for hydration and Centella asiatica
Centella asiatica
Centella asiatica is a small herbaceous annual plant of the family Mackinlayaceae or subfamily Mackinlayoideae of family Apiaceae, and is native to India, Sri Lanka, northern Australia, Indonesia, Iran, Malaysia, Melanesia, Papua New Guinea, and other parts of Asia...

for collagen conversion. A small study has shown an improved appearance of scars.

External links

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