What are Scars?
The term “scar” originated from the words “eschara” in Latin, “escharre” in French, and “eskhara” in Greek from the 14th century. These words literally mean hearth or fireplace, implying scabs produced subsequent to a burn. It was also related to the term “skar” from the Middle English, with literal meaning “crack, cut, incision.” [1, 2]
Scars are patches of skin developed over a wound after an episode of a previous injury, burn or cut. Included in the natural process of healing, these are fibrous tissues created from wound repair. They are often more erythematous, and thickened than the rest of the skin. [3, 4]
An image of an example of a scar, more darker and thickened than the rest of the skin.
Scar Formation Process
There are three layers of human skin: the epidermis, dermis and hypodermis. Once the dermal area is damaged, the dermal layer responds through the blood clot formation. It eventually produces fibroblasts, breaking down the clot and replacing it with collagen for scar tissue generation. 
Both the previous skin and the scar have the exact same component collagen. However, it is the fiber that makes the difference. In a normal uninjured skin, random collagen fibers follow a basket weave arrangement. In contrast to an injured fibrosed skin, the collagen cross links and follow an alignment. This particular arrangement of collagen in injured tissues, unfortunately, is less stable than that of the normal uninjured ones. 
An illustration of both normal (left) and scar (right) tissues, with the latter showing cross linking of collagen fibers.
Types of Scar Tissues
The type of scar formation is influenced mainly by the extent of skin injury, location of the wound, the duration of healing process, the age of the patient, and the skin tone.
Generally small in size, these scars are characterized as round depressions located beneath the surface of the surrounding skin. They are usually brought about by obliterated collagen fibers, interrupted skin restoration and insufficient formation of new fibers. These usually follow acnes and varicella infections. They are deemed to be the hardest scars to mend. [3, 6, 7, 8]
An image of atrophic scars brought about by acne.
2. Keloid Scars
These are raised, thick, irregular, hairless and shiny scars, larger and darker in hue, yet grew paler in time. They can be painful or pruritic, and feel hard and rubbery. They are considered as excessive tissue growth due to an overproduction of collagen in the area of wound, causing scar expansion in lieu of a completed healing process. These scars tend to be from injuries, surgeries and even piercings situated at the sternum, deltoids, ear lobes and shoulders. [6, 9, 10]
A photo of a patient with a keloid scar at her left deltoid.
3. Hypertrophic Scars
Similar to keloids, these are reddish in hue, thickened, raised, and either pruritic or tender. However, these differ from the former in its tissue growth, which is limited within the borders of the wound. They become visible 1 to 2 months after a secondary infection on the wound or a closure of the wound with excessive tensile strength. [6, 7, 10]
A photo of a hypertrophic scar at the left hand, with scar tissue limited within the boundaries of the injury.
Usually due to burns, these present when skin is pulled towards the site of injury. As a result, the skin tightens and restriction in movement is noted. [ 3, 9]
Contracture scars found at the neck.
5. Stretch Marks
Also coined as striae, these scars occur when the skin is expanded and lengthened far too rapidly. They are usually visible during pregnancy, growth spurts and significant weight gain. [2, 3, 11, 12]
A photo illustrating the presence of stretchmarks.
Minimizing Scar Tissues
The possibility of entirely removing a scar tissue is still under studies. However, there are ways wherein these scars can be minimized. These are usually done if there are pruritus, pain and restriction of movement.
These are utilized on the still healing skin to decrease inflammation and diminish keloid and hypertrophic scars. The sheets are applied on the scar for a duration of 12 hours per day for 3 months. 
Injection of Corticosteroids
These steroids can help improve the scars appearance, particularly the hypertrophic and keloid types, making them less visible. During the procedure, small injection of corticosteroids are administered on the scar to decrease swelling and ultimately flatten the scar. This is done on repeated doses at 4 to 6 weeks interval. [3, 9]
This procedure lessens the façade of both the hypertrophic and keloid scars. It requires freezing of the scar to a temperature lower than that of the normal skin. 
Dermabrasion induces resurfacing of the skin. This method uses a wire brush with rough edges in removing superficial layers of the skin, causing the skin to bleed. As wound healing ensues, new skin cells and tissues grow, replacing the removed damaged skin. [3, 7]
These are applied to soften and eventually flatten scars. In using such, an elastic material is placed over the scar 24/7 for a period of 6 to 12 months. They are often utilized for large skin grafts and burns. During the said process, silicone sheets are used as adjuncts. 
This can assist in concealing visible scars on the face. If water resistant, it can remain for 2 to 3 days. It uses a combination of needling and pigment application. [9, 13]
This is a non-invasive procedure using a fractional laser method to minimize scar rapidly. Its advantages include less pain, less risks and less waiting time. It diminishes redness by aiming on blood vessels located at the scar tissue. [9, 14, 15]
These are gels of hyaluronic acid base administered to areas of the face to minimize scars, particularly to the depressed areas of the face. When injected, the depressed areas will be filled and the contours further enhanced. However, these are short-lived, thus, repeated doses should be done for maintenance. [9, 16, 17, 18]
Surgical procedures for scar revision minimizes the scar in such a way that the tissue will be in closer proximity to the surrounding texture and tone of the skin. It can be done to change the scar shape, recover normal movement and of course, to improve appearance. [9, 19]
Preventing Scar Tissue Formation
Below are some ways which may be done during the healing process to minimize, or even prevent scars. 
- Aseptic wound cleaning and daily would care
- Use of pressure bandages
- Application of an anti-pruritic cream
- Making use of gels to sooth wounds and lessen redness
- Sheratt, J. Mathematical Modelling of Scar Tissue Formation. 2010. Department of Mathematics, Heriott-Watt University.
- Gauglitz, G, et al. Hypertrophic Scarring and Keloids: Pathomechanisms and Current and Emerging Strategies. Molecular Medicine. 2009; 1: 113-125.
- Young, G, et al. Creams for Preventing Stretch Marks In Pregnancy. 1996. Young, Gavin, ed.
- Elsaie, M, et al. Striae Distensae (Stretch Marks) and Different Modalities of Therapy: An Update. Dermatologic Surgery. 2009; 35(40): 563-73
- Tanzi, E. et al. Laser Treatment of Scars. Skin Therapy Letter. 2004; 9(1)
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