Keloid and Hypertrophic Scars: Keloid formation is one of the mysteries of human pathology. Especially mysterious is why similar injuries produce a keloid in one person and not in another. Why, in the same person, will an injury to the skin produce a keloid in one area of the body and not in another? Generally, a hypertrophic scar is a thickened scar at the site of an injury to the skin. This scar does not go beyond the border of the cut or surgical wound, whereas a keloid scar extends beyond the border. A keloid means a “crab-like” scar. A hypertrophic scar will flatten out spontaneously by one year. If the scar is still thickened after one year it will not usually flatten by itself. Keloid scars will often increase in size for many years.
The anterior chest area and outer shoulders are the most common sites for keloids but they can occur almost anywhere. The first evidence of an abnormal scar formation usually begins between the third and fifth week of healing. The growth of excessive scar tissue is rapid for six weeks and may continue at a slower rate for months to years.
KELOID SCARS - MANAGEMENT
DEFINITION: Hypertrophic scars remain within the confines of the original wound and usually regress spontaneously. Keloids extend beyond the wound in all dimensions and expand with time instead of regressing.
EPIDEMIOLOGY: Keloids are more common in darker pigmented races. Keloids may occur at any age but the average age of onset is 22 years for both men and women.
ETIOLOGY: Factors that play a major role in keloid development are:
Genetic Predisposition
Type of skin injury
Location (Deltoid, anterior chest, ear lobes)
Pregnancy
CLINICAL FEATURES
Hypertrophic Scars
Develop soon after injury
Regress with time (1 year)
Limited boundary
Size corresponds to injury
Keloids
May take many months
Do not regress with time
Grow beyond boundary
Minor wound may produce large keloid
Area of high incidence are shoulders, anterior chest, ear lobes
Rare on eyelids or genitalia
MANAGEMENT:
A) TOPICAL
Retinoids - Vitamin A acid
Steroids with occlusion
Silicone Gels (Fresh scars, less than 3 months)
B) INTRALESIONAL STEROIDS
Kenalog 10-40 mg/cc normal saline, not Xylocaine
mixed with hyaluronidase (Wydase)
Ligmaject technique
Intradermal, Emla
every 5-7 weeks
C) INTRALESIONAL 5 FU (R. Fitzpatrick)
mix with Kenalog
3 times per week
Maximum 100 mg per session
Best for hypertrophic scars and fresh keloids
D) CRYOSURGERY
liquid nitrogen jet spray
use cones
E) IRRADIATION
F) PRESSURE
Scars older than 6-12 months respond poorly
Pressure garments, devices are uncomfortable and must be worn day and night for 9-12 months
Effective pressure (25-40 mm Hg) not readily achieved in many anatomical areas
G) SURGERY
simple excision
W-Plasty best for faces
Z-Plasty not usually for faces (except for eyelids)
when combined with intralesional steroids leave sutures in 3-5 days longer
H) LASERS
1) High Energy pulsed CO2 lasers
Focused - excision mode
Vaporization - combined with Erbium Yag
Faces and ears only
2) Erbium Yag (used in combination with high energy pulsed CO2 laser)
3) Dualmode lasers
Er:YAG and CO2 Laser (DermaK, by ESC)
Pulsed Er:YAG Laser (Sequential ablation and coagulation/ Contour, by Sciton)
CO3 Laser by Cynosure variable pulse Er:YAG laser single pulse from 500 msec to 10 msec.