What is an abnormal scar?

Hypertrophic and Keloid Scars and their treatment options.

Hypertrophic scars

Primarily consist of type III collagen, which is aligned parallel to the epidermal surface, along with numerous myofibroblasts. The scar is elevated but stays within the borders of the original wound and usually regress after 6 months. HTS are more common than keloids, affecting approximately 10% of wounds. They tend to form in areas of tension, such as flexor surfaces.

Recurrence is less likely after excision and adjuvant therapy when compared to keloids.

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Hypertrophic scar in the neck

Keloid scars

The term "keloid" comes from the Greek word "chele," meaning "crab’s claw," due to its irregular growth pattern. Keloids continue growing beyond the original wound borders (do not regress) and are characterized by a disorganized collagen structure (types I and III) with very few myofibroblasts. Keloids can be influenced by genetic and hormonal factors, with more significant growth during puberty and pregnancy.

Recurrence: They rarely regress and are more resistant to excision and other therapies. Due to their high recurrence rates, multimodal treatment approaches are often recommended.

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Keloid scar

Treatment Options

• Corticosteroids

  • 10%-50% recurrence rate

  • Effective when used early to reduce scar formation

  • Combination treatments or repeated injection

• 5-Fluorouracil (5-FU)

  • 19% recurrence

  • Often used in combination with other treatments for better results.

• Cryotherapy

  • 50%-80% recurrence, with volume reduction

  • May not completely eliminate the scar, but can reduce its size.

• Surgical excision

  • Surgical excision alone has high recurrence rate (50–80%)

  • Surgical excision with steroid injection has intermediate recurrence rate (40–50%)

  • Surgical excision with postoperative radiation therapy has the lowest recurrence rate (10–30%)

• Radiation therapy

  • 2%-33% recurrence

  • Used post-surgery to prevent recurrence, but may cause skin damage.

  • Typically 3 fractions started on day 2 post-operatively.

1. Surgical Excision

• Effectiveness: Surgical removal has a high recurrence rate (50%-80%). Recurrence is reduced when combined with other treatments like steroid injections or radiation therapy.

2. Steroid Injections

• Mechanism: Reduce inflammation and fibroblast activity, preventing excessive collagen production.

• Effectiveness: Can significantly reduce the size and appearance of keloids, but repeated injections and/or combination treatment may be needed for optimal results. Side effects may include skin thinning or depigmentation, especially in darker-skinned individuals.

3. Postoperative Radiation Therapy

• Mechanism: Reduces fibroblast activity and collagen production in the scar tissue.

• Effectiveness: When given in three fractions after excision, it reduces recurrence rates to 10%-30%. However, it may cause skin ulceration, pain, and long-term risks such as skin aging or potential cancer risk, making it a last-resort option.

4. 5-Fluorouracil (5-FU)

• Mechanism: Inhibits fibroblast proliferation, reducing collagen overproduction.

• Effectiveness: Often used in combination with steroids for better results, particularly when steroids alone are insufficient. Potential side effects include irritation and inflammation at the injection site.

5. Fat Grafting

• Mechanism: Involves injecting fat (often with adipose-derived stem cells) into the scar tissue, promoting scar pliability and neoangiogenesis (formation of new blood vessels).

• Effectiveness: Improves scar flexibility and texture, particularly in areas previously treated with radiation, by regenerating healthy tissue.

6. Laser Therapy

• Pulsed Dye Laser (PDL): Targets blood vessels in the keloid, creating hypoxia, which reduces fibroblast activity and flattens the scar. Most effective when used on scars less than one year old.

• CO2 Laser and Er:YAG Laser: These lasers are used for scar remodeling by thinning hypertrophic or keloid scars, improving pliability, and promoting collagen remodeling. In both cases, several sessions are needed.

7. Cryotherapy

• Mechanism: Freezing the keloid with liquid nitrogen causes tissue breakdown, leading to scar flattening.

• Effectiveness: Often combined with steroid treatments to improve results. Cryotherapy may cause skin hypopigmentation (lighter skin), particularly in darker-skinned individuals.

8. Pressure Garments, Scar massage and Silicone Sheets

• Mechanism: Apply consistent pressure and hydration to the scar, increasing temperature and promoting scar remodeling.

• Effectiveness: Effective in preventing new keloid formation after excision, but not as effective once a keloid is fully formed. Pressure garments require continuous wear (24 hours a day) for effective results. Silicone sheets/gel should be used consistently for at least 3 months, starting 1–2 weeks after surgery. Aggressive scar massage several times a day by the patient starting 2 weeks postoperatively is very effective at improving scar pliability and appearance.

• Sun protection is mandatory for 6 months to prevent permanent scar hyperpigmentation.

Notable Mentions (that don’t work)

1. Onion Extract: Clinical evidence on its ability to prevent hypertrophic scars or improve scar appearance is mixed, with some studies showing limited benefits.

2. Vitamin E: Vitamin E mildly inhibits collagen synthesis. Most studies suggest it is not significantly effective in improving the appearance of scars.