GPadvice

Associate Professor Geoff Sussman

Scarring is part of the normal process of healing and in most instances is below the skin surface as the cross-linking of the collagen imparts tensile strength into the tissue. What is the process by which the body produces scar tissue and why do some people develop raised and unsightly scars?

Wounds gain only 20% of their final tensile strength in the first four weeks during collagen deposition. Tensile strength is slowly increased over the next six to twelve months however, at best; a scar is only 70-80% as strong as normal skin.

What is a scar?

A scar is connective tissue replacement of tissue which has been destroyed by injury or disease. Scar tissue is has no blood supply. It is pale, contracted and firm. Scar tissue is part of the normal healing cascade and is controlled by growth factors, specifically Transforming Growth Factor Beta [TGF-]. Collagen breakdown is controlled by enzymes and their activity is controlled by inhibitors produced by the cells.

Some people develop keloid and hypertrophic scars. These are benign fibrous growths and are characterized by excessive amounts of collagen. Keloids differ from Hypertrophic scars in that they continue to grow for years and tend to spread, invading the surrounding healthy skin beyond the wound margin.

The term keloid comes from the Greek ‘Chele’ crab’s claw due to its claw like appearance. Keloid and Hypertrophic Scars also develop secondary to wounds as a result of trauma - Insect Bites, Ear Piercing, Lacerations, Tattoos, Vaccinations and Burns. Hypertrophic scars are more common in burns and scalds.

Scars can produce both functional and cosmetic difficulties.

Why do some people scar more than others?
1. Genetic Basis [a positive Family History]
There is a ratio of 10:1 in dark skinned compared to the white skinned populations in scar development. This may be due to an abnormality of the Melanocyte Stimulating Hormone.

2. Skin and Tissue Tension
Increased tension at the skin will cause the scar to widen as the body reacts to the forces trying to separate the wound. Tension at the cellular level will also cause changes in enzyme activity and an increased collagen production, which is why some people develop more pronounced scarring.

3. Endocrine Factors; Increased Hormone Release.
Keloids enlarge during pregnancy and regress with menopause. Abnormal function of pituitary, thyroid, parathyroid and the hypothalamus may also be implicated

Hypergranulation
Hypergranulation is an overabundance of granulation tissue which is an impediment to normal wound healing. This will prevent the migration of the epithelium across the surface of a wound to close it. It is essential however to ensure that the tissue is in fact hypergranular as squamous cell carcinoma will have a similar appearance.

The management of hypergranulation has been the application of caustic materials such as silver nitrate or copper sulphate however a number of authors have called this process unacceptable. The use of hypertonic saline dressings eg. Mesalt® and Curasalt® covered with a foam dressing and then some external compression applied has been shown to be successful.

Treatment of scars
There are many methods used to treat scars. The best outcome is to prevent or minimize their formation by cellular manipulation and prevention.

Post surgery, especially where the incision is on an area of the body when movement is normal, for example the abdomen and joints, a technique is to reduce the tension at the suture line for a period after the sutures or clips have been removed.
The method is - on removal of sutures/clips place an elastic simple Steri - strip® (or similar) across the incision line. The strength of the union is enhanced by the covering of the strips with a film dressing. This remains in place for 7 -10 days and then changed.

As the sub-tissues mature over a period of many months, a film dressing is applied over the closed incision and replaced every 7 to 10 days over a four to five months period. This will also aid in a reduction of tension to the closed wound spreading of the tension across the total surface area of the dressing.

In the patient who has developed hypertrophic or keloid scars, there are a number of products with some success in reducing the appearance of these types of scars. It is common to see vitamin E cream being used on scars, while the application of a moisturizer will help keep the scar soft there is little published evidence of the value of vitamin E in fact there have been some claims made that vitamin E actually retards wound healing.

Silicone products have been used for a number of years to help reduce scarring and a number of these are available through pharmacy. The two commercial Silicone products are Cica-Care® and Mepiform®. There is also the silicone gel
Dermatix™ and an oil, Bio-Oil®.

Cica-Care ® gel sheet is a soft, self-adhesive, semi-occlusive sheet made from medical grade silicone reinforced with a silicone membrane backing.

Contra-indications
Cica-Care® is contra-indicated for patients with complicating medical factors which would make them unable to use the gel sheet properly and in patients with dermatological conditions which disrupt the integrity of the skin in areas of coverage. It is not to be used on open wounds.

Method of use
Cica-Care® is removed from the tray and a piece is cut to fit the size of the scar. The release liner is then removed and the adhesive side of the gel sheet is applied to the scar. Although self-adhesive, the product may also be held in place by a lightly elastic conforming bandage or tape. Cica-Care® should be washed in a mild, non-oily soap at least twice daily. Cica-Care® should be applied at least 12 hours per day and if possible it should be applied for 24 hours per day.

Frequency of Change
When Cica-Care® begins to wear or cleaning is difficult, it should be replaced. The usually occurs at 10-14 day intervals.

Warnings
In some patients, a rash has been observed on the covered skin. This has been attributed to either poor hygiene or to the product being applied with pressure too tightly. Should a rash appear, reduce Cica-Care® therapy time to 12 hours on, 12 hours off. If the rash persists, discontinue use and consult a physician.

Mepiform® is a thin flexible dressing consisting of a viscose nonwoven fabric bonded to a semi - permeable polyurethane membrane. The inner surface of the nonwoven is coated with a layer of soft silicone, which facilitates application and retention of the dressing to intact skin, but does not cause epidermal stripping or pain on removal. The dressing is waterproof but permeable to water vapour.

Indications
Mepiform® is designed for the management of both old and new hypertrophic and keloid scars.

Method of use
The skin contact surface of Mepiform® is protected by a plastic film that must be removed before use. A dressing should be selected that overlaps the area to be treated by at least one centimeter but larger dressings may be cut to size or shape before removal of the protective film if required.

If necessary, the area to be treated should be cleaned and then thoroughly dried. Then remove the dressing from the film and apply to the affected area with minimum tension, taking particular care to avoid stretching when applying over joints. Mepiform® is waterproof and can be worn while bathing and showering.

Frequency of Change
Mepiform® should ideally be worn 24 hours a day but may be removed once a day for inspection and washing of the skin. I leave it in place for 7 days and then change it.

Under normal conditions of use, a new dressing should be applied every 3 - 7 days or when the adherent properties of the dressing are no longer sufficient. It may take from 3 months to a year or more to improve and old scar depending upon the condition of the scar tissue.

Bio-Oil® is a specialist skincare product that helps improve the appearance of scars, stretch marks and uneven skin tone.
Dermatix™ is a transparent, fast-drying silicone gel is effective for the reduction of hypertrophic and keloid scars. It has also been successfully used for the treatment of scars resulting from trauma, burns and general surgical procedures. It should not be applied to open or fresh wounds. Application to mucous membranes or close to the eyes should be avoided. If redness, pain or irritation to the skin occurs, consult your physician or pharmacist.

Vitamin E has been used commonly for many years and applied topically to reduce scars. Bauman, in a double blind study found that topical Vitamin E did not help improve the cosmetic appearance of scars and leads to a higher incidence of contact dermatitis. In 90% of the cases in this study topical Vitamin E either had no effect on or actually worsened the cosmetic appearance of scars.

33% of the patients treated in the study developed a contact dermatitis to the Vitamin E.

References
Bauman, Dermatology Surgery 1999 25(4):311-315
International Clinical Recommendations on Scar Management Plastic and Reconstructive Surgery 2002 110(2):560-571
Bayat A et al, Skin Scarring BMJ 2003; 326:88-92
Quinn KJ et al, Non-pressure treatment of hypertrophic scars Burns1985; 12,102-108
Singer AJ et al, Mechanisms of disease: Cutaneous Wound Healing
New England Journal of Medicine 1999;3(10):738-746
Ahn ST et al; Topical Silicone gel for the prevention and treatment of hypertrophic scar; Arch Surg 1991(126) April: 499-504
Munro KJ, Hypertrophic and keloid scars Journal of Wound Care 1995:4(3):143-148
Poston J, The use of Silicone gel sheeting in the management of hypertrophic and Keloid scars.
Weller C, Sussman G, Wound Dressings Update; Journal of Pharmacy Practice and Research 318 Volume 36, No. 4, 2006: 318-324
Dunford C, Hypergranulation tissue Journal of wound care 1999 8(10):506-507