Why does a wound leave a scar ?
A scar appears when skin must produce new tissue to repair a deep lesion.
Very superficial damage limited to the epidermis may heal without leaving a true scar. When the dermis is affected, the body must rebuild the damaged area.
Fibroblasts produce collagen in particular to close and strengthen the wound. However, this new tissue is not identical to the original skin : its organisation and composition differ. This reparative tissue forms the scar.
The deeper the skin lesion, the greater the risk of a visible scar remaining.
Which lesions can cause a scar ?
Any sufficiently deep skin lesion can leave a scar. A scar is not a disease : it is tissue formed by the body to repair sufficiently deep skin damage.
Common causes include :
• Cuts and traumatic wounds when the dermis is affected.
• Surgical procedures.
• Deep burns.
• Bites and certain scratches when they penetrate deeply into the skin.
• Piercings and tattoos, which deliberately breach the skin.
• Certain deep skin infections or inflammation.
• Inflammatory acne, particularly when lesions reach deep into the dermis.
Why can acne leave scars ?
Acne can cause scars when inflammation damages the dermis and disrupts reconstruction.
Deep inflammatory lesions, particularly nodules and cysts, present more healing problems than superficial lesions.
When repair produces insufficient tissue, an atrophic or depressed scar may appear. Conversely, excessive scar tissue production may create a raised scar.
Manipulating, puncturing or squeezing inflammatory lesions can also increase local trauma and inflammation.
Why do some scars become wide or very visible ?
A scar may widen when the healing area undergoes substantial mechanical tension.
When movement or natural skin tension continually pulls on the wound, its edges are subjected to greater strain. Certain body regions are therefore more prone to wide or thick scars.
Slow healing, infection or prolonged inflammation can also promote a more visible scar. Mechanical tension is also a recognised factor in hypertrophic scarring.
A scar's appearance therefore does not depend solely on the initial injury's size.
Why do some scars become hypertrophic ?
A hypertrophic scar results from excessive scar tissue production during skin repair.
It becomes thick and raised but remains within the original wound boundaries.
Prolonged inflammation, slow healing and significant wound tension may promote development. Certain body areas are also more susceptible to this type of scar.
A hypertrophic scar may gradually flatten and soften as it evolves.
Why do some people develop keloid scars ?
A keloid scar corresponds to excessive, persistent scar tissue production extending beyond the original wound boundaries.
It may appear after surgery, injury, a burn, piercing, an acne lesion or sometimes relatively minor skin trauma.
Some people have an individual or family predisposition. Keloids are also more common in certain areas, particularly the chest, shoulders and earlobes, and in people with darker skin.
A keloid scar therefore differs from a hypertrophic scar by extending beyond the initial injury.
Why are some scars depressed ?
A scar becomes atrophic when repair does not restore enough volume to damaged tissue.
It then appears lower than surrounding skin.
Atrophic scars are particularly common after certain forms of acne. Their depth, width and shape may vary greatly.
A depressed scar, hypertrophic scar and keloid do not involve the same healing process and are not treated identically.
Why can a scar remain red or become darker ?
Scar colour evolves during maturation and does not depend solely on its height or depth.
A recent scar is frequently pink or red because of vascularisation. This redness may gradually diminish during maturation.
Inflammation can also alter pigmentation, creating an area darker or sometimes lighter than surrounding skin.
Colour and relief are therefore distinct characteristics : a scar can be flat but red, depressed and pigmented, or thick without substantial colour change.
When can a scar be treated with aesthetic medicine ?
Treatment depends above all on scar type : depressed, thick, red, pigmented or irregular.
Fractional lasers improve certain scars by acting on texture and collagen remodelling. Vascular lasers treat the red component.
A depressed acne scar, red surgical scar and hypertrophic scar do not require the same treatment.
Examining the scar identifies depth, relief, colour and stage of evolution to determine whether aesthetic medicine treatment is appropriate.
Article written by Dr Valeria Romano
Dr Valeria Romano supports each patient with a comprehensive approach to the aesthetics of the face, body and intimate areas, and to skin and hair quality. Every treatment is based on a personalised medical assessment.
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