Scars

There is a genetic predisposition in some people to produce thicker, itchy, enlarging scars called keloids.

Scarring is the process by which wounds and significant damage are repaired in complex animals. Damage to the deeper layer of the skin, the dermis, is required to produce a cutaneous scar. Damage to only the epidermis, the most superficial layer of skin, will not always produce a scar.

Scar tissue is different from normal tissue not only in architecture (lacking skin appendages such as oil glands, sweat glands, hair follicles, and pigment-producing cells) but also in the type of collagen present.

Although scarring and abnormal scarring can occur in all tissues of the body (cirrhosis in the liver, abdominal scarring leading to adhesions, Peyronie's disease, Dupuytren's contracture, etc), this paper will deal only with cutaneous scarring.

There is only one type of scar. The appearance of a scar depends on the nature of the wound that produced the damage, the anatomical location, orientation, and depth of the wound, the healing that occurred as the wound was healing, and a variety of systemic and genetic factors that are different for each individual.

If scar tissue is made over abnormal subcutaneous or deeper tissue, a depressed scar can result. Similarly, if scar tissue is made in an area of movement or tension or over a large area, a widespread scar can result. These types of scars can often be improved by surgical revision.

There are two types of excessive scar formation: hypertrophic scars are scars that are larger in amount and thickness than is necessary to heal the wound. Keloid scars, on the other hand, are larger and extend beyond the margins of the original wound. Although causation is similar, treatments are different for these two types of abnormal scarring.

The normal healing process in human tissue results in a scar. Scars occur when tissues have been significantly damaged and cannot be repaired with like tissue. Multicellular animals, particularly those with organs, have had to develop this means of survival and repair rather than replacement with like tissue due to the complex tissues that are in the body and the complex organ that the skin has become.

Scars can occur after physical trauma or as part of a disease process. For example, Hidradenitis suppurativa is a disease process involving the oil-producing glands of the skin, primarily in the axillary and inguinal areas. This disease process results in scarring, sinus tracts, and prolonged infection.

Four cardinal stages of wound healing are progressed through, sometimes at different rates and sometimes differently throughout an area of healing to finally produce a scar, which includes:

1. Hemostasis
2. Inflammation
3. Proliferation
4. Maturation or remodeling

Each of these stages is complex and biochemically regulated by large numbers of intrinsic and extrinsic wound healing factors. The control of these factors as well as placement, directionality, and knowledge of underlying structures is the purvue of surgeons and plastic surgeons in particular who try to optimize each of these scar attributes to produce the best possible scarring.

All wound healing depends upon good blood flow in the area of healing. There are procedures (touched on below) that may be required to bring this blood flow into an area of healing but these techniques are beyond the scope of this paper.

Scars occur at the site of tissue damage and appear as firm red to purple fibrous tissue that over time usually becomes flatter and lighter in color. Other symptoms may occur with stalled or abnormal wound healing.

Scars do not have the normal structure of the skin and, therefore, do not have oil or sweat glands, hair follicles, or pigmentation. This is the reason that mature scars are smooth, often shiny, and are always lighter in color than the surrounding skin. The inflammation that is necessary to bring in blood flow and healing cells and tissue can result in the darkening of the normal skin surrounding a scar (post-inflammatory hyperpigmentation). This can lead to the scar being more evident than it would be (since a scar has no pigmentation) had this not occurred.

Sometimes a scar can be revised and this process is controlled during the healing process so that the final scar is less evident. Hypertrophic and keloid scars can cause symptoms such as chronic pain or itching which can be improved with scar revision procedures.

Scars are almost always diagnosed by visual inspection. There are several rare situations when it may be necessary to examine scar tissue under a microscope to confirm its true identity. This would require a biopsy of the skin and may require the injection of a local anesthetic.

Sometimes other skin lesions can form in a cutaneous scar and require a biopsy to be diagnosed.

Since scars are the final result of the normal healing process, ordinary scars are not treated. Only when superficial scars become cosmetically or functionally undesirable do they require treatment. This would include scars in those who are predisposed to develop hypertrophic scarring or keloids, as well as scars in anatomical regions known to produce thick scars and scars that produce a significant, unpleasant distortion of adjacent anatomical structures. Scars on the flexor surface of joints (the surface of the joint on the inside of the bend), upon contracting, can lead to scar contracture which can limit joint movement. In these cases, the scar is often surgically released and reoriented if possible, or skin grafted so that joint movement is restored.

Hypertrophic scars and keloids often flatten out after injections of steroids directly into the fibrous scar tissue but, with the reduction in inflammation that the steroids act upon, thin or widespread scars can result. They can respond to the chronic application of pressure and the application of sheets of silicone rubber. Thick scars can be flattened by dermabrasion, which utilizes abrasive devices to sand down elevated scars.

Certain types of depressed scars can be elevated by the injection of a cosmetic skin filler or by fat injection under the scar tissue. This is often not successful due to the lack of blood supply in this area to maintain the viability of the fat cells. Subcision (subcutaneous release of the scar tissue through tiny incisions can be used in conjunction with fillers or fat to release the scar tissue and elevate it. Certain types of facial scarring respond well to forms of laser treatments. Occasionally, surgical revision of scars can result in a different scar that is much more cosmetically desirable.

Since it takes about a year for scars to mature and almost two years for complete remodeling, it is frequently prudent to wait before starting any invasive surgical revisions unless it is known that a poor scar will result in a given location.

Scar revision helps make the scar less noticeable and more cosmetically appealing; however, it does not erase it. Scar revision is also useful in restoring a poorly healed scar. Scar revision may include both surgical and non-surgical techniques. Complications of scar revisions can be reduced by proper planning and a surgeon's experience.

How is scar revision performed?

Cutaneous scar revision can be performed under local anesthesia, intravenous sedation, or general anesthesia. The plastic surgeon may recommend a combination of scar revision techniques to achieve optimal results. These include:

• Topical treatments: Gels, tapes, or external compression help in wound healing or reduce the skin’s ability to produce abnormal pigmentation. These may also help to treat existing surface scars and discoloration. It may also be useful during the healing of a new scar made during the scar revision procedure.
• Injectable treatments: Dermal fillers are useful in filling depressed or concave scars. The results may last anywhere from three months to several years, depending on the injectable substance. Therapy should be repeated several times to maintain results.
• Surface treatments: These involve cosmetic improvement of the scar. It evens skin irregularities and reduces uneven pigmentation. The different types of surface treatments include:
  • Dermabrasion is a mechanical polishing of the skin.
  • Laser or light therapy brings about changes in the surfaces of the skin, leading to the formation of new, healthy skin adjacent to the scar site.
  • Chemical peel solutions even out irregularities in texture and color by penetrating the skin's surface and blending it more gradually to the texture and lack of pigmentation in the scar itself.
  • Skin bleaching agents are applied topically to lighten the surrounding skin to blend with the scar tissue which has no pigment.
• Surgical excision: This may be required to surgically remove an old scar and replace it with a new one that is better oriented, to repair deeper structures that lead to the scar being depressed or whose progression can be manipulated to yield a better scar.

Some of the advanced techniques in scar revision include:

• Skin graft placement (split thickness of various depths up to full thickness)
• Local flap closure (simple to complex)Z-plasty, W-plasty, and reorienting flaps
• Distant flap closure and free flaps (moving skin with underlying muscle or even with bone into an area)

You cannot get rid of a scar with laser treatment. However, laser treatment can make a scar less noticeable. Laser treatment for a scar can be considered as an approach to revise the original scar to one with a less visible surface by blending it with surrounding, normal skin.

The treatment involves using a focused laser to either remove the outer layer of skin or stimulate the production of new skin cells to cover the scarred or damaged skin cells. Some lasers can reduce the redness of the scar itself although, with time, that generally happens with scar remodeling on its own.

The results of laser scar treatment depend on the skills of the person performing the treatment, the type of laser used, and the particular scar attributes that are trying to be improved. Sometimes, it is not the quality of the scar itself that is improved with treatment but, rather, the blending of a scar with its surrounding skin that makes it less visible.

You may need more than just the laser treatment to manage your scars. For example, if you have a deep acne scar, your doctor may perform a subcision followed by laser therapy followed by injecting a filler.

Good wound care is important in preventing excessive scarring as well as speeding up the healing process. Preventing infection can reduce unnecessary inflammation which can then result in better final scarring. Since inflammation is an integral component of wound healing, it is usually unwise to try to limit inflammation in an otherwise normally healing wound.

The environment of the healing wound is important in optimizing wound healing. Temperature, pH, presence of foreign bodies, blood flow, nutrient availability, and bioburden (presence of colonizing bacteria) are all considered in optimizing wound healing. A moist wound environment has been found to promote the best and fastest wound healing in contrast to the old practice of drying out wounds.

Assuming the wound is healing normally, it would not be unreasonable to cover the wound site after it is covered by skin (epithelialized) with silicone rubber 24 hours a day for a month or so. There is medical evidence that this can diminish the thickness of scars. Proprietary products of this type can be purchased without a prescription. There is an over-the-counter product (Mederma) that may improve the appearance of scars in the short term (first one to two months) but conclusive evidence of long-term scar improvement is lacking.

The judicious use of cosmetic makeup or even prostheses can effectively obscure many scars and skin or deeper tissue defects.

Scars generally improve in appearance over the first year and continue to remodel for two. So considerations for invasive treatments need to be prudently considered before that time. On the other hand, scarring usually involves tissue contraction, so it is unlikely that scars that pull or twist other anatomical structures or are depressed will improve. These should be treated sooner rather than later.

Scarring is the final result of a normal healing process. Assuming the wound does not become infected, optimizing the underlying tissue anatomy and blood flow as well as placement and orientation of the wound as well as the healing wound environment, as noted above, will result in the best possible cutaneous scarring.

Most medical insurance does not cover cosmetic procedures. If scarring has produced a change that is deemed other than cosmetic, it is reasonable to expect coverage, for example, when scarring results in functional loss, disruption of anatomy, or contractures. Occasionally, this question may be open to dispute so it can be helpful to have a physician's office intercede with the carrier before performing the procedure.