Scar

Scars are areas of fibrous tissue (fibrosis) that replace normal skin after injury. A scar results from the biological process of wound repair in the skin and other tissues of the body. Thus, scarring is a natural part of the healing process. With the exception of very minor lesions, every wound (e.g. after accident, disease, or surgery) results in some degree of scarring. An exception to this is animals with regeneration, 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, All keloid scars are hypertrophic Keloid scars can be caused by surgery, an accident, by acne 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 shoulders and chest. Hypertrophic scars and its subset Keloid tend to be more common in wounds closed by secondary intention. chickenpox, 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, 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.

Etymology

First attested in English in late 14th century, the word scar derives from Old French escharre, from Late Latin eschara, which is the latinisation of the Greek ἐσχάρα (eskhara), meaning "hearth, fire-place", but in medicine "scab, eschar on a wound caused by burning or otherwise".

Pathophysiology

ring one year after Road rash on the left, and the original wound on the right.]]

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.

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 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.

The myofibroblast are absent in the first trimester in the embryonic stage which heals scar free; 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. and is responsible for fibrosis on tissue Generally the myofibroblast disappear from the wound within 30 days;

As well as the fibroblast proliferation

Treatments

According to the American Academy of Dermatology, no scar can be completely removed although in some cases its appearance can be improved. 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 or ArteFill 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

Dermabrasion involves the removal of the surface of the skin with specialist equipment or not and usually involves a local anaesthetic.

Laser Treatment

Non-ablative lasers such as the 585 nm Pulsed Dye Laser, 1064 nm and 1320 nm , or the 1540 nm 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 or offer the best results for atrophic and acne scars. Like dermabrasion, 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.

Radiotherapy

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 are commonly used in preventing scar formation and improving existing scar appearance. Scientific evidence of efficacy is weak; however, and is likely due to increased hydration during and after healing.

Semiocclusive petroleum jelly- or dimethicone- based ointments are used to speed healing and reduce the appearance of scars and likely work in a similar manner as silicone scar sheets. Like with silicone sheets, scientific evidence regarding efficacy is weak.

Pressure dressings are commonly used in managing burn and hypertrophic scars, although supporting evidence is lacking.

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.

Surgery

(left), and photo 1 day after scar revision surgery. Area around sutures is still swollen from surgery]]

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.

Vitamins

Research shows the use of vitamin E and onion extract (sold under Mederma) as treatments for scars is ineffective.

Intentional scarring

The permanence of scarring has led to its intentional use as a form of body art within some cultures and subcultures (see scarification). These forms of ritual and non-ritual scarring practices can be found in many groups and cultures around the world.

Research

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 (RSK) in the formation of scar tissue and found that the introduction of a chemical to counteract RSK could halt the formation of Cirrhosis. This treatment also has the potential to reduce or even prevent altogether other types of scarring.

Research has also implicated osteopontin in scarring.

A research group in South Africa has a combination approach using a microporous tape in addition to Bulbine frutescens for hydration and Centella asiatica for collagen conversion. A small study has shown an improved appearance of scars.

See also

Scarification

Self-injury

Wound healing

Dueling scars

References

External links

WebMD.com article

American Academy of Dermatology: "What is a scar?"

Ohio State University Medical Center article

International Scar Meeting in Tokyo 2010 International Scar Meeting

Category:Diseases involving the fasciae Category:Greek loanwords