Hypertrophic Scars

Overview

A hypertrophic scar is a thick, raised scar that develops when the body produces too much collagen as a wound heals. Collagen is the protein that gives skin its structure, and during normal healing the body lays down just enough to repair the injury. In a hypertrophic scar, the healing process is overactive, leaving a firm, raised area of scar tissue.

Unlike keloid scars, which grow beyond the edges of the original wound, hypertrophic scars stay within the boundaries of the injury. They are most likely to form on areas of high tension or movement and after burns, surgery, or deep cuts. Many hypertrophic scars improve gradually over months to years, and a range of treatments can help flatten and soften them.

Symptoms

Hypertrophic scars have a recognizable appearance and feel:

• Raised, thickened skin over the site of a healed wound.
• A red or pink color early on, which often fades over time.
• A firm or rubbery texture.
• Itching or tenderness, particularly while the scar is still forming.
• Tightness or restricted movement if the scar crosses a joint or covers a large area.

A key feature is that the scar remains within the borders of the original wound and does not spread into surrounding healthy skin. The scar may continue to change in appearance for many months as it matures.

Causes

Hypertrophic scars form when the body's wound-healing response produces an excess of collagen. Factors that contribute include:

• Skin injury, such as burns, surgical incisions, deep cuts, piercings, and acne.
• Wound tension, as scars over areas that stretch or move frequently, like the shoulders, chest, and joints, are more prone to thickening.
• Delayed or complicated healing, including wound infection or prolonged inflammation.
• Repeated irritation or pressure on a healing wound.

The tendency to form thick scars also varies from person to person, suggesting that individual healing characteristics play a role.

Risk Factors

Certain factors make hypertrophic scars more likely:

• Burns and large or deep wounds.
• Wounds under tension or over joints and areas of frequent movement.
• Wound infection or delayed healing.
• Younger age, as scars in children and young adults can be more reactive.
• A personal tendency toward thick scarring, which may run in families.

Diagnosis

Hypertrophic scars are usually diagnosed by appearance during a physical examination. A clinician looks at the scar's size, color, texture, and location, and asks about the original injury and how the scar has changed over time.

An important part of the assessment is distinguishing a hypertrophic scar from a keloid. Hypertrophic scars stay within the wound's borders and often improve over time, while keloids extend beyond the original wound and may continue to grow. A skin biopsy is rarely needed but can be done if the diagnosis is uncertain.

Treatment

Many hypertrophic scars soften and flatten on their own over time, but several treatments can speed improvement and ease symptoms. The choice depends on the scar's size, location, and age:

• Silicone gels and sheets, applied over the scar for several weeks to months, are a common first step to flatten and soften it.
• Pressure therapy, such as pressure garments, often used after burns.
• Corticosteroid injections to reduce thickness, itching, and redness.
• Laser therapy to improve color and texture.
• Cryotherapy (freezing) for some scars.
• Surgical revision in selected cases, usually combined with other treatments to lower the chance of the scar returning.

Massage and moisturizing may also help. Treatment is often more effective when started while the scar is still maturing.

Prevention

Good wound care can reduce the likelihood of a hypertrophic scar forming:

• Keep wounds clean and watch for signs of infection.
• Follow your healthcare provider's instructions on caring for surgical or burn wounds.
• Protect healing scars from the sun, which can darken them.
• Avoid putting tension on a healing wound and consider supportive taping or silicone products if you are prone to thick scars.
• Treat acne and skin infections to limit deeper skin damage.

When to See a Doctor

Consider seeing a healthcare provider or dermatologist if a scar:

• Is thick, raised, itchy, or painful and bothers you.
• Limits movement, especially over a joint.
• Continues to grow or spreads beyond the original wound, which may suggest a keloid.
• Causes significant distress about appearance.

A clinician can confirm the type of scar and recommend treatments that work best when started early. Seek prompt care if a wound or scar shows signs of infection, such as increasing redness, warmth, swelling, pus, or fever.

Related Topics

Frequently Asked Questions

References

1. American Academy of Dermatology.
2. Mayo Clinic. Scars.
3. MedlinePlus, U.S. National Library of Medicine.
4. DermNet.