Keloid scars present as a
thickened, raised skin-coloured lesions at the site of surgery
or trauma. It is important differentiate keloid from hypertrophic
scars. Both are elevated due to deposition of excess collagen
within the dermis. Keloid scars grow progressively and behave
like tumours invading the surrounding normal skin. Hypertrophic
scars are confined to the area of tissue damage. Hypertrophic
scar usually regress with time whereas keloid scars usually
do not.
Keloids are seen more often in patients of West African and
Asian origin. Within these population groups some people are
more susceptible than others but no common genetic defect
has been identified. They can occur at any age but are more
common in adolescence and early adulthood. Both sexes are
equally affected. They almost always occur after injury or
surgery. 'Spontaneous' keloids have been described but these
are more likely to arise from trivial injury that has been
forgotten by the patient. The extent of keloid formation is
invariably out of proportion to the degree of tissue damage.
Disfiguring lesions can occur after apparently minor trauma.
They are more common on the skin of the presternal area, neck,
ears and proximal limbs. The incidence is reduced in scars
placed along lines of election (Langer's lines).
During normal wound healing, from three days to three weeks,
a period of proliferation occurs during which collagen deposition
exceeds collagen lysis. There then follows a period of equilibrium
before a late phase of remodeling occurs. During this later
phase collagen lysis exceeds collagen deposition and scar
thins. The strength of the scar is maximal at four to six
weeks. Remodelling is complete by one year. In keloid scar
formation this ordered sequence is deranged with collagen
deposition far exceeding lysis.
No treatment of keloids has been shown to be uniformly effective.
Surgery is unfortunately associated with a high risk of recurrence.
It may be of use in keloids that occur as a result of post-operative
wound infection or from poorly placed incisions. If further
surgery is contemplated post-operative pressure from elastic
compression garments may help to prevent recurrence. Physiotherapy
may be a useful adjunct as also may be topical silicone gel
sheets. These have been shown to be particularly useful in
post-burn hypertrophic scars. Cryotherapy, laser and both
external beam and intra-lesional radiotherapy have been used.
The use radiotherapy is controversial as it does induce regression
of keloid scars but concerns exist that it may induce skin
tumours.
The most extensively used drug treatment is topical or intra-lesional
injection of the long-acting steroid, triamcinolone. Steroids
reduce collagen synthesis by decreasing mRNA production and
shifting collagen metabolism in favour of lysis. Whilst reducing
the extent of keloid scarring complications including skin
atrophy, hypopigmentation and telangiectasia are not uncommon.
Interferon-gamma has recently been used with encouraging results.
Recent Papers
Ahn S T, Monafo W W, Mustoe T A. Topical silicone gel for
the prevention and treatment of hypertrophic scar. Arch Surg
1991; 126: 499-504.
Mustoe T A, Cooter R D, Gold M H et al. International clinical
recommendations on scar management. Plast Reconstr Surg 2002;
110: 560-571
O'Sullivan S T, O'Connor T P, O'Shaughnessy M. Aetiology
and management of hypertrophic scars. Ann R Coll Surg 1996;
78: 168-175.
Poston J. The use of silicon gel sheeting in the management
of hypertrophic and keloid scars. J Wound Care 2000; 9: 6-10.
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