Keloids are benign overgrowth of fibroblasts when wounds are repairing that cause disfigurement. In normal wound healing there is initial proliferation of fibroblasts to produce the scar tissue; in patients predisposed to keloid scarring there is excessive and prolonged activation of keloids (likely due to poor control of TGF-beta). Although the exact pathogenesis remains to be determined, there are strong racial and genetic predispositions to the disease (often those of African descent).
Diagnosis is suspected by the presence of excess tissue that extends beyond a healed wound. Keloids are often uncomfortable and itchy. They can sometimes grow to significant size. There appears to be no role for biopsy of keloid. An important differential is hypertrophic scarring, where there is increased tissue that is limited to the wound and does not extend locally.
Avoidance is the best option as there are no established treatments with good cure rates and acceptable toxicity profiles.
- Patients should not undergo piercing (ear, lip etc) as they may develop large, cosmetically disastrous keloids in the face region
- Pigmented skin lesions should only be removed if there is a significant index of suspicion
- Acne should be controlled aggressively (eg. isotretonin)
- Other skin disorders should also be managed aggressively to prevent healing with keloid scarring
If surgery is required, tactics that may reduce keloid incidence include:
- Pressure (typically used for ear piercings; clamps can be applied to the ear that may reduce the development of keloid)
- Silicon dressings may reduce the development of keloid
For established keloid, several different approaches have been used:
- Intralesional steroid (triamcinolone) shows good response rates (up to 60-70%); this can avoid surgery and radiotherapy if successful. It is important to use a very small needle (27 or 29 gauge - I wonder what colour those are?)
- Surgical excision removes the keloid but up to 50% of patients will develop recurrence at the tumour site.
- Radiotherapy is sometimes recommended for keloid. The potential for second malignancies as well as long term cosmetic effects limits its application, particularly for young patients. The first fraction of radiotherapy must be administered within 24 hours of surgery. Superficial x-rays are typically used unless the treatment site is extensive, in which case electrons may be necessary. The typical dose ranges from 8 Gy in 1 fraction to 15 Gy in 5 fractions, 3 fractions per week.
- Other therapies include cyrotherapy and intralesional 5-FU, although these are not in frequent use.
The patient is clinically marked up immediately post-operatively. The surgical scar with a 1 cm margin is the field edge. Superficial x-rays are used (100 kV). The dose is typically 15 Gy in 5 fractions (3 Gy/#) but a variety of strategies are in place.