From the Guidelines
Hypertrophic scars and keloids are distinct types of raised scars with different characteristics, prognoses, and treatment approaches. The primary difference between hypertrophic scars and keloids lies in their growth patterns, with hypertrophic scars remaining within the original wound boundaries and keloids extending beyond these boundaries 1. Hypertrophic scars typically appear within 4-8 weeks after injury, may improve or flatten over time, and are often red, raised, and firm but respond well to treatments. In contrast, keloids can appear months after injury, rarely regress without intervention, and are typically larger, more raised, and darker than hypertrophic scars.
Key Characteristics
- Hypertrophic scars:
- Remain within the original wound boundaries
- Appear within 4-8 weeks after injury
- May improve or flatten over time (usually within 1-2 years)
- Often red, raised, and firm
- Respond well to treatments
- Keloids:
- Grow beyond the original wound boundaries
- Can appear months after injury
- Rarely regress without intervention
- Typically larger, more raised, and darker than hypertrophic scars
- Often appear shiny and smooth
- Tend to be more persistent and difficult to treat
Treatment Approaches
Treatment for hypertrophic scars and keloids overlaps but differs in intensity. Hypertrophic scars may respond to less aggressive treatments, while keloids generally require more aggressive interventions such as intralesional steroid injections (triamcinolone 10-40 mg/ml), pressure therapy, silicone sheeting, cryotherapy, or even surgical excision followed by radiation in severe cases 1. Understanding these differences is crucial for proper diagnosis and treatment selection, especially considering the genetic predisposition and higher incidence of keloids in individuals with darker skin tones, particularly those of African, Asian, or Hispanic descent. Prevention is key, especially for individuals with a personal or family history of keloids, who should be cautioned about the risks associated with scarification and other body modification processes 1.
From the Research
Definition and Characteristics
- Hypertrophic scars and keloids are both types of excessive scarring, resulting from an abnormal wound healing process with excessive collagen deposition 2, 3.
- They can be disfiguring, functionally and aesthetically, and have different clinical and histochemical characteristics 4, 5.
Differences between Hypertrophic Scars and Keloids
- Hypertrophic scars and keloids have distinct clinical courses and physical appearances, defining them as separate entities 5.
- Keloids are characterized by dysregulated growth with excessive collagen formation, extending beyond the original wound boundaries 3.
- Hypertrophic scars, on the other hand, remain within the boundaries of the original wound and tend to regress over time 5.
Treatment Options
- Various treatments are available for hypertrophic scars and keloids, including conventional therapies, surgical therapies, and adjuvant therapies 2, 3, 6.
- Prevention of keloid and hypertrophic scars remains the best strategy, and patients with a predisposition to develop excessive scar formation should avoid nonessential surgery 2.
- Treatment options include radiation, pressure therapy, cryotherapy, intralesional injections of corticosteroid, interferon, and fluorouracil, as well as topical silicone or other dressings, and pulsed-dye laser treatment 2, 3.
Pathophysiology and Risk Factors
- The pathophysiology of keloid and hypertrophic scars is not completely understood, but various cytokines and growth factors have been implicated, including interleukin-6, interleukin-8, and transforming growth factor-beta 3, 6.
- Risk factors for developing keloid and hypertrophic scars include genetic predisposition, skin tension, and wound depth 6.