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Scars (also called cicatrices) are areas of fibrous tissue (fibrosis) that replace normal skin (or other tissue) after injury. A scar results from the biologic 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.

Scar tissue is not identical to the tissue that it replaces and is usually of inferior functional quality. For example, scars in the skin are less resistant to ultraviolet radiation, and sweat glands and hair follicles do not grow back within scar tissue. A myocardial infarction, commonly known as a heart attack, causes scar formation in the heart muscle, which leads to loss of muscular power and possibly heart failure. However, there are some tissues (e.g. bone) and all original non wounded tissues that can heal without any structural or functional deterioration.

A very minor scar from a cut to the forearm, approx. one year since the wound.

The word scar was derived from the Greek word schara, meaning place of fire (fireplace).[1]

Contents

How scarring occurs

Hypertrophic scarring one year after Road rash on the left, and the original wound on the right.

A scar is a natural part of the healing process. Skin scars occur when the deep, thick layer of skin (the dermis) is damaged. The worse the damage is, the worse the scar will be. Most skin scars are flat, pale and leave a trace of the original injury that caused them. The redness that often follows an injury to the skin is not a scar, and is generally not permanent (see wound healing). The time it takes for it to go away may, however, range from a few days to, in some serious and rare cases, a few years. Various treatments can speed up the process in serious cases. Scars form differently based on the location of the injury on the body and the age of the person who was injured. To mend the damage, the body has to lay down new collagen fibers (a naturally occurring protein that is produced by the body by fibroblasts). In wounded tissue these fibers are over expressed with collagen, but not so in non wounded tissue. Stable forms of topical vitamin C have been shown to improve collagen formation[2]. Recent research has also implicated the gene product osteopontin in scarring and University of Bristol have developed a gel that inhibits the process[3][4].

An injury does not become a scar until the wound has completely healed. And because the wounded body tissue over expresses collagen on the fibers and cannot re-build, the new tissue will have a different texture and quality than the surrounding normal tissue. This collagen producing process results in a fortuna scar.

Transforming Growth Factors (TGF) play a critical role in scar development and current research is investigating the manipulation of these TGFs for drug development to prevent scarring from the emergency adult wound healing process. As well, a recent American 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.[5]

Abnormal scars

Two types of scars are the result of the body overproducing 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, but do not grow beyond the boundaries of the original wound, and they often improve in appearance after a few years. Keloid scars are a more serious form of scarring, because they can carry on growing indefinitely into a large, tumorous (although benign) growth. Keloid scars can occur on anyone, but they are most common in dark-skinned people.[6] 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.

Alternately, a scar can take 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 or muscle, are lost. This type of scarring is commonly associated with acne, but can be caused by chickenpox, surgery or an accident.

Scars can also take the form of stretched skin. These are called striae and 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.

Treatments for skin scars

According to the authority aad.org no scar can be completely removed.[7] Although non wounded tissues, bone healing, healing in embryos and some animals even after extended injuries can and do regenerate without scarring.[8]

Currently the treatments available are not effective in removing all the scar. A number of approaches have been tried with silicon gel sheeting and steroid injections having the most widely accepted role in general scar treatment.[9]

In historical sequence, corticosteroid therapy by injection into the scars was introduced in the 1960s, from the early 1970s pressure garment therapy was introduced for widespread burn scars, and silicone gel sheets from the 1980s.[10]

In 1971 Moss & Clifford produced scar free healing,[11] but unfortunately their work went unnoticed.

Needling

Needling is an inexpensive process where the scarred area is continuously needled to promote collagen formation. Once needled the area is allowed to fully heal, and needled again if required depending on the intensity of the scar. Scarring needles and needling rollers are available for home use; however, needling should not be done on parts of the face or areas where major nerves are located without professional medical supervision. Needling at home must also be done in line with hygienic and sterilization requirements.

Pressure garments

Pressure garments should be used only under supervision by a medical professional. They are most often used for burn scars that cover a large area, this treatment is only effective on recent scars.

Pressure garments are usually custom-made from elastic materials, and fit tightly around the scarring. They work best when they are worn 24 hours a day for six to twelve months.

It is believed that they work by applying constant pressure to surface blood vessels and eventually causing scars to flatten and become softer.

Steroids

A long term course of steroid 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.[12]

Silicone sheeting and gel

Silicone scar treatments improve scar appearance and are often used to prevent and treat hypertrophic scarring. The exact mechanism of action is unknown though some studies suggest a manipulation of local ionic charges or a decrease in production of “pro-inflammatory” substances like TGFβ2.[13]

Dimethicone silicone gel appears to be as effective as silicone sheeting in improving scar appearance.[14]

Dermabrasion

Dermabrasion involves the removal of the surface of the skin with specialist equipment and usually involves a general anaesthetic. It is useful with raised scars, but is less effective when the scar is sunken below the surrounding skin.

Collagen injections

Collagen injections can be used to raise sunken scars to the level of surrounding skin. Its effects are however temporary, and it needs to be regularly repeated. There is also a risk in some people of an allergic reaction.

Laser surgery & resurfacing

The use of lasers on scars is a new form of treatment. Several cosmetic lasers have been FDA approved for the treatment of acne scars by using laser resurfacing techniques. Vascular lasers have been proven to greatly reduce the redness of most scars 6–10 weeks after the initial treatment. It has been theorized that removing layers of skin with a carbon dioxide or Erbium:YAG laser may help flatten scars.[citation needed]

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

Surgery

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.

Radiotherapy

Low-dose, superficial radiotherapy, is used to prevent re-occurrence of severe keloid and hypertrophic scarring. It is usually effective, but only used in extreme cases due to the risk of long-term side effects.

Natural remedies

Research shows the use of vitamin E and onion extract as a treatment for scars is ineffective. Vitamin E causes contact dermatitis in up to 33% of users and in some cases it may worsen scar appearance.[12][15] Vitamin C normalizes collagen production and encourages the production of an organized, healthy collagen framework [16] which improves scar appearance. Vitamin C and some of its esters also fade the dark pigment associated with some scars.[2]

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.

See also

References

  1. ^ Online Etymology Dictionary
  2. ^ a b Farris PK. Topical vitamin C: a useful agent for treating photoaging and other dermatologic conditions. Dermatol Surg 2005;31:814-818.
  3. ^ http://jem.rupress.org/cgi/content/abstract/205/1/43 'Molecular mechanisms linking wound inflammation and fibrosis: knockdown of osteopontin leads to rapid repair and reduced scarring'
  4. ^ BBC NEWS | Health | Gel 'to speed up wound healing'
  5. ^ "Liver damage 'could be reversed'". BBC News. 27 December 2007. http://news.bbc.co.uk/2/hi/health/7152415.stm. Retrieved 2008-01-01. 
  6. ^ Martini, Frederic H. (2006). Fundamentals of Anatomy & Physiology, Seventh Edition, p. 171. Benjamin Cummings, San Francisco.
  7. ^ "What is a Scar". American Academy of Dermatology.. 2008. http://www.aad.org/public/publications/pamphlets/cosmetic_scar.html. Retrieved 2008-06-08. 
  8. ^ ""Scar prevention: The healing touch"". Nature volume=436: 1079-1080. 25 August 2005. http://www.nature.com/nature/journal/v436/n7054/full/4361079a.html. 
  9. ^ Ziegler UE (2004). "[International clinical recommendations on scar management]" (in German). Zentralbl Chir 129 (4): 296–306. doi:10.1055/s-2004-822830. PMID 15354252. 
  10. ^ Kelemen O, Kollár L (2007). "[Current methods of treatment and prevention of pathologic scars]" (in Hungarian). Magy Seb 60 (2): 63–70. PMID 17649846. 
  11. ^ "Methods Of Promoting Scar-Free Healing Of Skin Lacerations". freepatentsonline.com. 1971-11-23. http://www.freepatentsonline.com/3622668.html. Retrieved 2010-2-19. "Surprisingly, scar-free healing has resulted, even without sutures, for extremely deep and wide lacerations that traditionally require four or more stitches." 
  12. ^ a b Jenkins M, Alexander JW, MacMillan BG, Waymack JP, Kopcha R. Failure of topical steroids and vitamin E to reduce postoperative scar formation following reconstructive surgery. J Burn Care Rehabil. 1986 Jul–Aug;7(4):309–312.
  13. ^ Kuhn MA, Moffit MR, Smith PD, et al. Silicone sheeting decreases fibroblast activity and downregulates TGFbeta2 in hypertrophic scar model. Int J Surg Invest 2: 467, 2001.
  14. ^ Mustoe TA. Evolution of silicone therapy and mechanism of action in scar management. Aesth Plast Surg 2008;32:82–92.
  15. ^ Baumann LS, Spencer J. The effects of topical vitamin E on the cosmetic appearance of scars, Dermatol Surg. 1999 Apr;25(4):311-5.
  16. ^ Fitzpatrick RE, Rostan EF. Double-blind, half-face study comparing topical vitamin C and vehicle for rejuvenation of photodamage. Dermatol Surg 2002;28:231-236.

External links


Simple English

A scar is the natural result of a healing process in the human body. When the deeper layer (scientists call that dermis) is hurt by a wound, the wounded tissue will be replaced by scar tissue. Scar tissue is not identical to the tissue it replaces. A scar will look different (and have different characteristics) than the surrounding tissue.

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