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Scars are available in all shapes, sizes and colours and are the results of the pores and skin’s natural healing process after damage, whether or not it is attributable to surgical procedure, an infection, harm or fast physique development.
Scars serve an essential function: They allow the physique to exchange misplaced or disfigured tissue. However what are scars fabricated from? And why are they everlasting?
To reply these questions, first it’s a necessity to make clear what a scar is.
The pores and skin is fabricated from three main layers. The outermost layer of pores and skin, generally known as the dermis, is the thinnest layer. It is composed of layers of flattened cells, referred to as epithelial cells, which collectively act as armor, defending the physique from the skin world.
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Beneath the dermis is the dermis, the thickest layer of pores and skin that incorporates nerves, blood vessels, hair follicles and sweat and oil glands. Throughout the dermis, there may be additionally a big, fibrous community of proteins referred to as collagen and elastin that, respectively, support the structure and elasticity of the skin. Lastly, the hypodermis is the deepest layer of the pores and skin. It incorporates fatty tissue for insulating the physique, cushioning inside organs and shielding tissues from harm.
In the event you harm solely the dermis — corresponding to normally of sunburn — this outer layer of pores and skin will just peel off, leaving the deeper layers of pores and skin intact. But when an harm penetrates deep into the dermis, the physique then has to restore this broken tissue. A scab types to seal the wound, after which irritation initiates healing. Then, the pores and skin begins to transform the tissue inside that wound, and the haphazard approach it does that is what causes a scar to kind.
In regular pores and skin, the dermis’s community of collagen fibers is sort of a piece of material that’s fastidiously woven in a pleasant, easy sample, Dr. Damon Cooney, an affiliate professor of plastic and reconstructive surgical procedure at Johns Hopkins Drugs, instructed Reside Science. If an harm tears this material, the physique makes new collagen fibers to fill in any gaps.
Nevertheless, as a substitute of properly weaving the brand new fibers again collectively throughout the wound, the physique dumps all of them collectively in a jumbled pile, Cooney mentioned. This disorganized buildup of collagen makes up most scar tissue, making it look completely different from — and move less flexibly than — regular pores and skin.
Scar tissue additionally differs from unscarred pores and skin in that it doesn’t contain any hair follicles or sweat glands. In folks with lighter pores and skin, a scar could first seem pink or purple, however over time, this coloration will fade and the scar will grow to be slightly lighter or darker than their regular pores and skin coloration. The scars of individuals with darker pores and skin will usually appear to be darkish spots.
Generally, the physique continues to put down collagen inside scar tissue for longer than it usually would, inflicting what’s generally known as a keloid or a hypertrophic scar to kind. These are thick, raised scars that may be purple, pink or purple, or simply subtly darker than an individual’s regular pores and skin tone. Keloid scars are larger than the original wound, whereas hypertrophic scars are the identical dimension.
Adolescents and pregnant girls are more likely to develop hypertrophic scars than different teams, probably due to hormonal changes that boost inflammation within the physique. Keloid scars are extra widespread in folks with darker pores and skin tones, likely due to genetic risk factors.
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Scars can fade over time because the jumbled collagen fibers inside them start to flatten and easy out, Cooney mentioned. This course of can take round six to 18 months. How a lot a scar fades depends upon its size, location and type. Nevertheless, scars by no means absolutely disappear, as a result of the jumbled tissue stays essentially completely different from the pores and skin round it.
In concept, there may very well be a technique to set off scar-free therapeutic in people. Some animals, like salamanders, can completely regenerate wounded skin, leaving no scars behind. People also can do that, however solely as fetuses, during the first two trimesters of pregnancy. Past that time, we lose the flexibility to regenerate wound tissue, and scientists do not actually know why.
Animal studies have proven that pores and skin transplanted from an grownup to a fetus will nonetheless scar. This implies grownup pores and skin cells are programmed in a approach that causes them to scar, quite than regenerate, after harm. Variations within the number and location of stem cells inside pores and skin may clarify why solely fetal wounds regenerate. Nevertheless, this analysis continues to be in its infancy.
The “pie within the sky” objective could be to develop a remedy that enables the physique to modify from scarring to regeneration, Cooney mentioned.
Within the meantime, some remedies can scale back the looks of scars. As an illustration, laser therapy can change the colour and top of a scar, whereas massaging a scar, particularly with silicone gel sheets, might help easy and flatten it, Cooney mentioned.
Different therapy choices embrace scar revision, whereby medical doctors surgically take away a scar and create a brand new one that’s extra uniform in look. Steroid injections also can reduce the size of hypertrophic and keloid scars. These injections assist disband the collagen fibers in these scars and scale back the irritation that may trigger the tissue inside it to swell.
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