Keloid Scars

A keloid scar is one in which there is overgrowth of dense fibrous tissue. This usually develops after the injury has healed. It extends beyond the borders of the original wound. It does not normally regress spontaneously, and it will usually recur after excision.

The normal wound healing process involves an anabolic and a catabolic stage that should be in equilibrium about 6 to 8 weeks after the injury. At this stage, the strength of the wound is about 30 to 40% that of healthy skin but as the scar matures cross-linking collagen fibres add strength. As this occurs, it may be thickened, but this subsides gradually over the following months until a flat, white, pliable, possibly stretched, mature scar has developed.

When the anabolic component exceeds the catabolic phase of the healing process, more collagen is produced than is degraded, and the scar grows in all directions being raised above the level of the skin. Excessive scar tissue is classified either as a keloid or a hypertrophic scar.

In 1806, Alibert¹ coined the term cheloide, from the Greek chele, meaning crab's claw, to describe the lateral growth of tissue into unaffected skin.

• All races may be affected but there is a marked racial difference in terms of predisposition.
• It is more common in Chinese and Polynesian people than Indians and Malays but the highest incidence is amongst those whose racial origin is sub-Sahara Africa. It is regarded as normal and African tribal scars are based on the predisposition to keloid. These are often three parallel lines on the cheeks of young men. It is least common in those of European ancestry and is rare in albinos.
• It is more common in those of certain HLA tissue types and blood group A. A genetic predisposition has been suggested, both autosomal dominant and autosomal recessive.

The reason to consult about a keloid scar is usually cosmetic although they may be tender, painful, itch or produce a burning sensation.

• There is usually a history of trauma that may be accidental, surgical or cosmetic. Keloid is quite often seen in the scar after a coronary artery bypass graft. It may affect the ear lobe after cosmetic piercing.
• The scar has grown beyond the original line of trauma and may have done so in a very irregular way. It is often raised.
• It feels soft, rubbery or like dough.
• It is red in the early stages but becomes brown or pale with age.
• There are no hair follicles or sweat glands within the scar.
• The natural history is variable. Most lesions continue to grow for weeks or months but others grow for years. Growth is usually slow, but keloids can enlarge rapidly, growing much bigger in a matter of months. When they stop growing, they do not usually cause symptoms and remain stable or regress slightly.
• On the ears, neck, and abdomen keloid may be pedunculated. On the central chest and extremities, they are usually raised with a flat surface, and the base is often wider than the top.
  Most keloids are round, oval, or oblong with regular margins but some have a claw-like appearance with irregular borders.
• Most people have just 1 or 2 keloids but some have many more. Some may develop spontaneous keloids, or they may have developed from acne or chickenpox.
• Keloids over a joint can contract and restrict movement.

Distribution

• In European races, keloids present most often and in decreasing order of frequency, on the face, especially cheeks and earlobes, upper extremities, chest, presternal area, neck, back, lower extremities, breast, and abdomen.
• In Afro-Caribbean people, the order of frequency is earlobes, face, neck, lower extremities, breast, chest, back, and abdomen.
• In Asian people, the descending order of frequency is earlobes, upper extremities, neck, breast, and chest.

There is no specific investigation that is required.

The fact that there are so many possible treatments for keloid is testament to how unsatisfactory is the treatment. A combination approach probably offers the best results.² Amongst the options are:

• Occlusive dressings include silicone gel sheets and dressings, as well as other substances and a number of proprietary tapes. They may have to be worn with compression for 24 hours a day for up to a year and about a third get an excellent result, a third a satisfactory result and a third an unsatisfactory result. A Cochrane review was unimpressed by the quality of trials for silicone sheeting and felt unable to make any recommendation.³
• Compression therapy is often used in conjunction with other modalities including occlusive steroid applications.
• Intralesional corticosteroid injections reduce collagen formation. Sometimes the old scar is excised and steroids are injected into the new one as it forms. Otherwise the new scar is likely to be as unsightly as the old. Most studies cite a success rate of less than 50%.
• Cryosurgery with liquid nitrogen may be used over 20 to 30 days with improvement in half to three quarters of cases.
• Excision is usually used in conjunction with other modalities. Used alone, the recurrence rate exceeds 50%. Excision as part of combination therapy would appear to be the safest and most effective technique.⁴
• Radiation therapy is controversial as there is risk of later malignancy as we know from the use of Grenz rays for acne and other skin conditions. The risk of skin malignancy after therapy does appear to be low but the evidence of efficacy of this treatment that has been used since 1906 is also dubious.⁵
• Laser therapy has been used with various different types of lasers and variable results.
• Interferon therapy has limited experience. Other interesting substances to affect scar formation include verapamil, bleomycin, 5-fluorouracil, retinoic acid, imiquimod, tacrolimus, and botulinum toxin. Imiquimod as a 5% cream induces tumour necrosis factor alpha (TNFα) and appears to be effective.⁶ Tacrolimus is an immunomodulator that inhibits TNFα.
• Other new therapies are directed at collagen synthesis.⁷

By and large, the quality of research to assess treatments is poor. Patients must be followed for at least a year to assess recurrence.

If an individual has a predisposition to keloid formation, it is important to look to prevention for the future. Those who have keloids only on the earlobes are not necessarily at risk.

• Avoid surgery unless essential. Avoid piercing.
• Close all surgical wounds with minimal tension.
• Incisions should not cross joint spaces.
• Avoid making incisions along the mid-sternal line, and ensure that incisions follow skin creases whenever possible and Langers lines.