Hypertrophic Scarring

Why hypertrophic scarring happens

When a wound reaches the dermis (the deep layer of skin), the body repairs it in stages: inflammation, then new tissue formation, then remodeling. Cells called fibroblasts produce collagen to fill the gap. Normally they slow down once the wound closes, and the collagen is reorganized into a flatter scar.

In hypertrophic scarring, the repair phase does not switch off. Fibroblasts and contractile cells (myofibroblasts) keep producing collagen in tight nodules, and extra small blood vessels grow in. The result is a scar that is thick, raised, red and stiff. The inflammation also triggers itching and tenderness.

Anything that prolongs inflammation or stretches the wound edges keeps this process going:

• Wound tension: skin over the chest, shoulders, upper back, joints and neck is constantly pulled.
• Slow healing: wounds that take more than about 2 to 3 weeks to close, including deep burns, are much more likely to thicken.
• Infection or wound breakdown.
• Repeated irritation: friction, ingrown hairs, acne or piercings.

Who is at risk

• Burn injuries: hypertrophic scarring follows a large share of deep burns. See burns.
• Younger people: children, teenagers and young adults heal more vigorously.
• Darker skin types: people of African, Asian and Hispanic heritage scar more often, though anyone can.
• Personal or family history of thick scars.
• Location: sternum (breastbone), shoulders, upper arms, earlobes, and across joints.
• Surgery types: midline chest operations, cesarean sections and joint surgery.

Hypertrophic scar vs keloid

If a scar is still growing outward after a year, it is probably a keloid. Single-scar diagnosis and photos of each type are covered on the hypertrophic scar page.

Symptoms

• a raised, firm, ridged scar, usually 1 to 5 mm above the skin
• red, pink or purple color that fades slowly
• itching, often worse in heat or at night
• tenderness or a pulling sensation
• tightness that limits movement when the scar crosses a joint (a contracture, see joint contracture)

Preventing hypertrophic scarring

Prevention starts the day of the wound:

1. Help the wound close quickly: keep it clean, moist (petroleum jelly under a dressing) and protected. Seek care early for deep cuts so they can be closed.
2. Treat infection promptly.
3. Reduce tension: paper tape or silicone strips across a surgical scar for the first 6 to 12 weeks limit stretching.
4. Start silicone early: silicone gel or sheets once the wound has fully closed, usually around 2 weeks, for at least 2 to 3 months. They hydrate the scar and calm fibroblast activity. Sheets work best worn 12 hours or more a day.
5. Protect from sun: SPF 30+ or covering to stop the scar darkening.
6. Pressure garments after burns: custom-fitted garments worn about 23 hours a day for 6 to 12 months or more reduce thickening of large burn scars.

How to flatten a hypertrophic scar

Most scars respond best to a combination of treatments, started early.

First-line treatments

• Silicone gel or sheets: the best-supported home treatment, for new and established scars. Use for at least 2 to 3 months to judge results.
• Scar massage: firm, circular massage for a few minutes several times a day, once the wound is stable, softens scars.
• Pressure: pressure garments, clips for earlobes or tape.

Treatments from a doctor

• Corticosteroid injections: triamcinolone injected into the scar every 4 to 6 weeks flattens and softens it and relieves itching. Side effects include thinning of the skin, lighter patches and visible small vessels.
• Steroid tape or plasters: for smaller scars, especially in children who dislike injections.
• 5-fluorouracil injections: sometimes combined with steroid for resistant scars.
• Laser treatment: pulsed dye laser reduces redness and itch; fractional lasers improve thickness and texture, including in burn scars.
• Cryotherapy: freezing can flatten small raised scars but may lighten darker skin.
• Surgery: scar revision or Z-plasty can release contractures and reposition tension. Because hypertrophic scars often improve with time, surgery is usually delayed for at least 12 months unless a contracture limits function.

Managing itch

Moisturizers, cool compresses, silicone and oral antihistamines (follow the label dose) can help. Steroid injections often relieve itching quickly.

Outlook

Hypertrophic scars usually improve. Many flatten and fade considerably over 1 to 2 years, especially with silicone and pressure. They rarely disappear completely, and burn scars across joints may need therapy or surgery to keep full movement. General information on how scars mature is on the scarring page.

Frequently asked questions

Do hypertrophic scars go away on their own?

Often partly. Most hypertrophic scars soften, flatten and fade over 12 to 24 months as the collagen remodels. They seldom disappear completely. Treatment with silicone, massage and pressure speeds improvement and gives a better final result.

How do you flatten a raised scar at home?

Use silicone gel or silicone sheets daily for at least 2 to 3 months, massage the scar firmly for a few minutes several times a day, and protect it from the sun. Pressure from tape or garments helps larger scars. If there is no improvement after 3 months, ask about steroid injections.

What is the difference between a hypertrophic scar and a keloid?

A hypertrophic scar stays within the boundaries of the original wound, appears within weeks, and often improves over time. A keloid grows beyond the wound into surrounding skin, may appear months later, rarely regresses on its own, and often returns after being cut out.

Why is my scar raised and itchy?

Raised, itchy scars are usually hypertrophic. Too much collagen and extra blood vessels make the scar thick and red, and inflammation releases chemicals that cause itching. It is most common in the first 6 months. Silicone, moisturizers and, if needed, steroid injections relieve it.

Can you prevent hypertrophic scarring after surgery?

You can lower the risk. Keep the wound clean and moist, avoid stretching it, use paper or silicone tape for support, start silicone gel once it closes, and protect it from the sun. People prone to thick scars should tell their surgeon, who may use extra tension-reducing techniques.