Scars: Causes, Types, Prevention & Treatment

What is a scar?

A scar is any break affecting the living tissue caused by a cut, blow, or another impact, typically one in which the skin is cut or broken. The human skin can easily be hurt, which often results in remaining consequences – uneven and conspicuous scars.

The final appearance of a scar depends on many factors, including the skin type and location affected, the direction of the wound, the type of injury, the age of the person who got injured and so on.

Skin is one the largest organ of the human body and its’ most important defender. The Skin constantly interacts with the environment by participating in the process of thermoregulation and sensation.

In order to maintain its functions, after being broken, it regenerates the formation of a scar in place of the injury.


Scar on arm

The scar is newly formed connective tissue which replaces normal skin structure after skin disease or injury. The shape and size of the scar depend on the type of the lesion.

The color of the mark is determined by the moment of the trauma occurrence. Fresh scars are usually pink or red and, as time passes, they begin to fade. As the scar continues to heal sometimes the tissue turns white, which is known as hypopigmentation.

Scar tissue is different from the normal skin, it is usually smooth and shiny (atrophic).

Connective tissue in this area does not contain sebaceous and sweat glands or hair follicles, but is very well vascularized and innervated. Therefore, some of the signs can include severe pain or reduced sensitivity in the affected area.

Scars result from inflammatory skin diseases (most commonly acne) or after the loss of skin integrity and injuries, burns, surgery or other injuries where the dermis is affected.

If the skin wound is superficial (e.g. a slight scratch) it affects the epidermis (top layer of the skin). Superficial wounds usually heal without forming scars.

When both the epidermis and dermis (deep layer of the skin placements) are damaged wounds heal with scar formations.

How are scars formed?

The scar is the final phase of the process of wound healing. Typically, this process is well controlled by the body and normally takes place in the following three successive phases:

First phase

Inflammatory phase. This is the primary response of the body to the tissue damage and lasts from 3 to 5 days. In phase 1 the dead tissue is removed as well as the eventual contaminants.

Second phase

Proliferative (formation of new tissue) phase. Cytokines and growth factors secreted during the inflammatory phase, stimulate the process of proliferation. It started the third day of the injury and continues 3rd-6th week. Proliferative phase takes place with the formation of granulation tissue.

Third phase

Remodeling phase. The proliferative phase is replaced by a long period of progressive remodeling and scar healing of the wound. The collagen matrix, under the influence of cytokines and growth factors, is successively degraded, synthesized again, reorganized and stabilized. Fibroblasts gradually disappear as collagen type III, deposited during the granulation phase, is being replaced by healthy collagen type I.

Fibroblasts gradually disappear as collagen type III, deposited during the granulation phase, is being replaced by healthy collagen type I.

The process of scar formation can last from 6 to 12 months.

Scar Healing
Scar Healing Process

How to avoid scars?

In order to prevent scarring after minor injuries, you should not remove the scar crust formed on the wound. You should also avoid wearing tight clothes covering the affected area.

Injury or abrasion should not be treated with oily based remedies.

The unhealed wound must be kept dry. It is recommended to be careful while washing and bathing since wetting the wound can catalyze inflammatory processes leading to scar formation.

Depending on the scar location, the healing process continues between 6 and 12 months.

During this period, the wound should be protected from exposure to sunlight, as the UV rays stimulate the hyperpigmentation of the scar as well as the growth of new connective tissue, leading to its’ roughening.

It is recommended to apply photoprotective agents until the complete healing of the wound.

The scars, especially the fresh ones should not be exposed to extreme temperatures (saunas, strong cooling, etc.).

You should carefully perform any sorts of physical exercises and movements, in order to avoid stretching the skin of the affected areas.

The post-burn and chemical scars should be treated special pads for skin tightening as well as greasy ointments.

What are the different types of scars?

The wide range of scars is influenced by gender, age, race of the individual, as well as the hormonal balance, hereditary predisposition, and other factors.

In general, the scars may be divided into hypertrophic and atrophic

Atrophic scars are skin depressions, which are caused by destruction or loss of collagen. They are generally below or at the level of the skin and may be the result of trauma, surgery, inflammatory diseases (acne, chicken pox) etc. This group includes:

Fine line scars

They are a thin pale/ pigment line, which can be barely noticeable. Most often this type of scars are disposed on different areas of the skin that are not subjected to stretching, they are very well vascularized. They can also occur in areas that are not prone to the formation of hypertrophic scars or keloids. Fine line scars are the result of knife injuries, scratches, surgery, trauma, and others.

Fine Line Surrounding Eye
Fine Lines

Wide scars

They result from an inflammation process or a gradual stretching and expanding the fine lines of the surgical scars, which usually occurs during the 3 healing weeks or within 2 – 3 months after surgery. They are usually flat, pale, soft, asymptomatic scars, often after surgeries in the areas subjected to stretching, such as knees, back, shoulders etc.

WIde scar
Wide Scar

Stretch marks

They are long, narrow streaks, stripes or lines that develop on the skin and which differ in hue from the surrounding skin. They are the result of a sudden stretching of the skin and are extremely common. Their color can vary from whitish to purplish.

Stretch Marks
Figure 1: Multiple cutaneous striae at thigh

Predisposing factors for the occurrence of stretch marks can be pregnancy, fast growth, fast weight gain/weight loss; particular diseases – conditions such as Cushing’s syndrome, hormonal imbalance, prolonged use of corticosteroids.

Acne scars

The most common scars are the atrophic acne scars [1]. During the healing process of the skin, resulting in the occurrence of inflammation affecting the deep dermis, there may be changes in collagen synthesis and subsequent atrophy of the skin.

Acne Scars
fig7: Needling: patient before the treatment.

Such scars can be with different size, depth and shape depressions (cave-ins). Acne scars can be divided into the following categories:

Icepick Scars

Appearance: deep, very narrow, extending into the dermis. The skin looks as if it was stabbed by an ice pick or some sharp instrument. “Icepick” scars can leave deep “holes” in the skin, some may look like large open pores.

Development: such scars appear after cyst infection or other serious inflammation.

Skin tissue is destroyed and on the affected area.

Boxcar Scars

Appearance: These scars are round or oval depressions with steep vertical sides.

Development: they are the result of an inflammatory process leading to the destruction of subcutaneous fat, and collagen, resulting in depression.

The skin in this area is left without and/or with a small amount of underlying tissue. These scars may be superficial to severe, depending on the amount of tissue loss.

Rolling Scars

Appearance: This type of wave-shaped scars forms unevenness across the normal skin. These scars can also become more noticeable as we age.

Unlike the “icepick” and “boxcar” scars, “rolling scars” are broad (4-5 mm) and shallow.

Development: Rolling scars arise when fibrous bands of tissue appear between the skin and its’ subcutaneous layer.

Hypertrophic scars

Appearance: Hypertrophic scars are common, wide, and raised. They are bright pink (in a light skin), are uniform, and do not extend beyond the edge of the original incision. Hypertrophic scars caused by acne most commonly found on the upper parts of the body, especially in men.

Development: In contrast to the various types of atrophic scars (described above), hypertrophic scars are not caused by loss of tissue (e.g. skin burns).

They continue to thicken for 3 to 18 months, then become static, and finally resolve to become broad, soft, thin, and level with the surrounding skin; the whole process taking about three years.

Hypertrophic scars
Figure 0002: A patient with burn scar before and after treatment

Keloid Scars

Appearance: They are also wide and raised, but the new tissue grows beyond the original confines of the scar to form irregular mounds of collagen, which resemble benign tumors.

Development: Keloids are less common, but are not unusual in African patients. Keloids may not start to form for many months after the original breach of the skin surface; they grow for a year or more, and then stop. There may be so many of them, and they may be so large, that they disfigure, deform, and disable the patient.

Keloids are difficult to treat. If you excise one through normal skin and graft the gap, it is likely to recur around the edges of the graft, or in any gaps or splits in it.

Most often they affect the upper chest and the back, ears, shoulders and chin.

They stand out above the surrounding skin (from a few mm to 2-3 cm). They rarely cause pain but are often accompanied by intense itching and discomfort.

Keloid Scar
Keloid formed after an operation. One year since surgery. The wound caused by the motorcycle accident and stitched up.


Scars treatment depends on many factors. It can be:


It can be performed by the topical application of  scar gels and creams, silicone bands, etc.;


When skin integrity is impaired, it is necessary to be performed a surgical, corticosteroid or laser treatment.

Scar surgeries

These are meant to minimize the scar so that it is more consistent with the surrounding skin tone and texture. Scar revision [2] can provide a more pleasing cosmetic result or improve a scar that has healed poorly. The procedure involves removing the entire scar surgically and rejoining the skin. As a result, a new scar will form.

Such surgery aims to create a less obvious scar. Surgical scar revision is usually done on wide or long scars, scars that healed in an unusual way, or scars in very visible places. However, a scar cannot be completely erased.

Corticosteroid injections

„Corticosteroid injections for prevention and treatment of keloids and hypertrophic scars are perhaps the first-line option for family physicians. Corticosteroids suppress inflammation and mitosis while increasing vasoconstriction in the scar.”

These types of injections can help soften and then shrink hard scars. Keloids and hypertrophic scars often soften after intralesional steroid injections [3].

Collagen Injections

Collagen (derived from purified cow collagen) is injected beneath the skin [4]. The purpose of such treatment is to replace the body’s natural collagen that has been lost.

Injectable collagen is generally used to treat wrinkles, scars, and facial lines.

Laser treatment

Laser therapy [5] includes noninvasive treatment sessions. This treatment uses powerful fractional laser technology to reduce the look of scars (short pulses of micro-fine laser light to reach deeply into the skin’s sub-layers, treating the skin’s support structure.

Then the body’s natural healing process sweeps away older, damaged tissue and rebuilds it with fresh, new collagen and elastin (the crucial building blocks of normal-looking skin) without harming the surrounding skin.

After several sessions (depending on the skin condition), scars are less visible and the skin looks smoother than before the procedure.


The procedure helps reduce the size of scars by freezing the top skin layers [6]. Such freezing causes the skin to blister.

Chemical Peeling

Chemical peeling [7] is used to minimize sun-damaged skin, irregular color (pigment), and superficial scars. During the procedure, the top layer of skin is removed with a chemical application to the skin.

By removing it, the skin regenerates, often improving its’ appearance.

Home remedies

Below are some home remedies for scar removal that can fasten the healing process.

Recipe 1:

4 teaspoons lemon juice; 3 tablespoons yogurt; 4 tablespoons honey; 1 egg white

All ingredients are mixed together in order to form a homogeneous paste. Apply the mixture on the scar tissue for about 15 minutes. Wash with lukewarm water.

Repeat the procedure once a week. A few weeks later you will be able to notice the improvement.

Recipe 2:

Another effective treatment against scarring is the baking soda. You’ll be surprised how effective and useful it can be in almost any situation. It helps to return the youthful glow on your skin and baking soda participates in the composition of the best creams for removal of scars.

Take 5 tablespoons of baking soda and mix with 1 tablespoon of water to get a thick paste. Apply on the affected skin and let it dry. Then rinse with warm water. Repeat 3 times a week.

Recipe 3:

Sweet almond oil mixed with wheat and argan oil. Mix the ingredients in equal parts, into a homogenous paste, and apply the cream in circular motions on the problem areas every day.

Recipe 4:

Soak a gauze into diluted raw Apple Cider Vinegar and apply on the problem areas and repeat the same procedure daily until the scar tissue is restored.

For older and bigger scars you will need to be more persistent and continuously apply the ointments.

Recipe 5:

Castor oil is one of the cures for scars that offers plenty of vitamins A and E.

Twice a day the heated oil is applied to the skin. Leave the oil for least two hours. This procedure is done until the scar has completely faded.


    Acne Scarring
    Overview of Surgical Scar Prevention and Management
    Are corticosteroids effective for prevention of scar formation after second-degree skin burn?
    Collagen Injections
    Medical Lasers
    Use of Intralesional Cryosurgery as an Innovative Therapy for Keloid Scars and a Review of Current Treatments
    Chemical Reconstruction of Skin Scars Therapy Using 100% Trichloroacetic Acid in the Treatment of Atrophic Facial Post Varicella Scars: A Pilot Study

About the author

Monika Hristova

Monika is the Editor-in-Chief at SkinPractice. She is a skin care addict and researcher, who feels strongly about helping people with different dermatology conditions from alopecia to warts.

You can read her recommendations and advice both here at SkinPractice or at Quora where she answers skincare-related questions frequently and is the most viewed author in the Skincare category with more than 3 million views or follow her on LinkedIn.

She is also a certified skin care specialist with certification from the Medical College in Sofia.

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