Keloid Scar: Causes, Symptoms and Treatment

What Is a Keloid Scar?

A keloid scar (or simply a keloid) is a benign but often troublesome form of excessive scar tissue that grows beyond the edges of the original wound or skin injury. Unlike hypertrophic scars, which remain within the wound boundaries, keloids invade the surrounding healthy tissue. They are composed primarily of disorganized collagen fibers and can continue to grow for months or even years after the initial injury.

Causes

The exact cause of keloid formation is not fully understood. It is believed that an overactivation of fibroblasts (the cells responsible for producing connective tissue) during the wound healing process plays a central role. Known triggers include:

• Surgical incisions, burns, or traumatic wounds
• Piercings or tattoos
• Acne scars or chickenpox scars
• Insect bites or vaccination sites
• Genetic predisposition (family history of keloids)

Certain groups are more susceptible: individuals with darker skin tones (of African, Hispanic, or Asian descent) and younger people between the ages of 10 and 30 are at higher risk of developing keloids.

Symptoms

Keloid scars can vary significantly in appearance and the symptoms they cause. Common signs and symptoms include:

• A shiny, raised scar that extends beyond the wound margins
• Reddish, purplish, or brownish discoloration
• Itching and a burning sensation in the affected area
• Tenderness or pain when touched
• Restricted movement when keloids develop over joints

Keloids most commonly develop on the shoulders, chest, earlobes, and cheeks.

Diagnosis

Keloid scars are typically diagnosed through a clinical examination by a dermatologist or surgeon. The scar is visually assessed and the medical history is reviewed (e.g., timing of the injury and growth behavior of the scar). In rare cases, a skin biopsy may be performed to rule out other conditions such as dermatofibrosarcoma. Imaging studies are generally not required.

Treatment

Treating keloid scars can be challenging and often requires a combination of approaches. Recurrence after treatment is possible. The following treatment options are available:

Conservative Treatment

• Corticosteroid injections: Cortisone is injected directly into the keloid to suppress collagen production and flatten the tissue. This is the most commonly used first-line therapy.
• Silicone gel or silicone sheets: Regular application to the scar to regulate moisture and apply gentle pressure.
• Compression therapy: Pressure bandages or compression garments to mechanically inhibit scar growth.

Surgical and Interventional Treatment

• Surgical excision: Removal of the keloid, usually combined with other therapies, as the recurrence rate with surgery alone is high.
• Cryotherapy: Freezing the keloid with liquid nitrogen to destroy the tissue.
• Laser treatment: Pulsed dye laser or CO2 laser to reduce redness and tissue volume.
• Radiation therapy: Low-dose radiation applied immediately after surgical removal to prevent recurrence.

Newer Approaches

• 5-Fluorouracil (5-FU): A cytostatic agent injected into the keloid to inhibit cell division.
• Bleomycin injections: Another agent used to suppress collagen production.

Prevention

Complete prevention of keloids is difficult for individuals with a genetic predisposition. However, the following measures may help reduce the risk:

• Careful and gentle wound care after injuries or surgical procedures
• Early use of silicone products once the wound has closed
• Avoiding unnecessary skin procedures (piercings, tattoos) if a tendency toward keloid formation is known
• Sun protection on fresh scars to minimize pigmentation changes

References

1. Berman B. et al.: Keloids and Hypertrophic Scars - Pathophysiology, Classification, and Treatment. In: Dermatologic Surgery, 2012.
2. Rabello F.B. et al.: Update on Hypertrophic Scar Treatment. In: Clinics (Sao Paulo), 2014; 69(8): 565-573.
3. Gold M.H. et al.: Updated International Clinical Recommendations on Scar Management. In: Dermatologic Surgery, 2014; 40(8): 825-831.