Scar tissue replaces normal skin tissue after the skin is damaged. Though scar tissue is made up of the same substance as undamaged skin, it looks different because of the way the fibers in the tissue are arranged. Scars form every time the skin is damaged beyond its first layer, whether that damage comes from a cut, burn, or a skin condition like acne or a fungal infection. Though there are ways to minimize the appearance of scars, there is no way to remove them entirely.
How it Forms
Human skin is made up of three main layers, the epidermis, dermis, and hypodermis. When the dermis — the pink middle layer in the cross-section of skin — is injured, the body first responds by making blood clot in the area to close off the wound. After the blood clots, the body then sends in fibroblasts, a type of cell that helps rebuild skin tissue. These cells break down the clot and start replacing it with proteins, primarily collagen, that make up scar tissue.
Though both scar tissue and normal skin are made with these collagen proteins, they look different because of the way the collagen is arranged. In regular skin, the collagen proteins overlap in many random directions, but in scar tissue, they generally align in one direction. This makes the scar have a different texture than the surrounding skin. Scar tissue is also not as flexible as normal skin, and does not have a normal blood supply, sweat glands, or hair.
Types of Scar Tissue
How an individual scar looks depends on a few things, including the circumstances of the injury and a person's skin tone. For instance, a puncture wound causes a different looking scar than a burn wound, and whether the wound gets infected or not can also influence the appearance of the scar. A wound in a place where the skin is stretched tight, like the chest, often causes a thicker scar, since the body has to make more tissue to keep the wound from pulling open. Skin tone plays a role too. Though scars in general tend to turn white over time, those with dark skin may get scars that get darker with time. Those with darker skin may also be more prone to keloid scars.
There are five main types of scars:
- Atrophic scars: These scars are sunken down into the skin. This type of scarring is often seen with acne scars or with wounds where skin or muscle is removed by an injury. This type of scarring can also happen when the body produces so much scar tissue in one area that it prevents new cells from growing where the wound took place.
- Hypertrophic scars: These are usually red or purple and are slightly raised above the skin. They tend to fade and get flat over time.
- Contracture scars: These types of scars often happen with burns, and end up pulling the skin in towards the site of the injury. This can make the skin look puckered around the wound.
- Keloid scars: These are very elevated, red or dark scars that form when the body produces a lot of extra collagen in a scar. Keloid scars are actually a benign type of tumor, and often grow bigger than the area of the original injury. Those with darker pigmented skin are thought to be more prone to keloid scarring, but it's not clear why.
- Stretch marks: Also called striae, these are considered a unique type of scar since they don't happen in response to an injury, but because of the skin being stretched rapidly, often during pregnancy or adolescence. The tissue here is often sunken a little into the skin, and tends to fade with time.
Preventing and Treating Scar Tissue
Though there is no way to entirely get rid of scar tissue aside from avoiding a skin injury, there are ways to minimize its appearance both while the wound is healing and after a scar has formed. Except for keloid scars, most scars will fade on their own even without treatment.
While the wound is healing:
- Covering the wound with a bandage — This is particularly important before going out in the sun, since UV rays can cause the newly formed tissue to get discolored and may slow down the healing process.
- Cleaning wounds properly — Doctors recommend cleaning a wound with a gentle soap and lukewarm water. Cleaning with hydrogen peroxide, alcohol, or iodine can all damage the newly forming cells and lead to a more noticeable scar.
- Soothing gels — Rubbing aloe vera gel on the skin after the wound has closed can help lessen redness. Vitamin E gels are not recommended, since studies show that they are not very effective are minimizing scars.
- Anti-itch cream — This can help with the urge to scratch or touch the healing wound, which could irritate it and make a more noticeable scar.
- Pressure bandages — Some doctors say that putting a specific type of pressure bandage on a wound can help prevent the appearance of elevated scars since it pushes the collagen down. There are several different brand name versions of these bandages, which are often called scar therapy bandages or scar sheets.
Ways to minimize scars after they form:
- Massage — Massaging a scar with lotion or a doctor-recommended gel can help fade many types of scars. This is particularly recommended for keloid scars, since this can keep them from getting sensitive and painful, and can help break down some of the built-up collagen.
- Injections — Steroid injections may help with hypertrophic or keloid scars, and atrophic scars can sometimes be filled in with collagen injections. One downside to this type of treatment is that it is almost always temporary, and has to be repeated regularly.
- Skin resurfacing — This can be done with lasers or with equipment that works like very fine sandpaper in a procedure called dermabrasion.
- Cryotherapy — This is a technique of freezing the scar, and can reduce the appearance of keloid and hypertrophic scars.
In extreme cases, a doctor might recommend surgery. Though surgery can't get rid of a scar, it can make it less noticeable. Surgery is not recommended for hypertrophic or keloid scars though, since it can make them worse. Another type of treatment for severe scars is radiation therapy, which can sometimes reduce keloid and hypertrophic scars.
Video 1 — Information from a plastic surgeon about how scars form and how surgeons avoid making noticeable scars.
Video 2 — Information about keloid scars.
www.ma.hw.ac.uk — Information on how scars form, with illustrations.
www.webmd.com — Information about treating scars after they form.
http://practicalplasticsurgery.org — A PDF with information on the how scars from and ways to treat problematic scars.