Hypertrophic Scars

What is a hypertrophic scar?

When skin heals, cells called fibroblasts lay down collagen to close the gap. Normally, production slows once the wound has closed, and the scar matures into a flat, pale line over months. In a hypertrophic scar, inflammation persists and fibroblasts keep making collagen in thick, disorganized bundles. The result is a scar that is:

• raised above the surrounding skin, usually by a few millimeters
• red or pink, sometimes darker in brown or Black skin
• firm, sometimes itchy or tender
• confined to the shape of the original wound

Hypertrophic scars typically appear within 4 to 8 weeks of the injury, grow for a few months, then gradually mature.

Hypertrophic scar vs keloid

These two raised scars are often confused, but they behave differently.

A raised bump on a nose or ear piercing is usually a hypertrophic scar or a "piercing bump" (granuloma) rather than a keloid. It usually shrinks with good aftercare and silicone. True keloids on the earlobe tend to be larger and keep growing.

Causes and risk factors

• Burns: especially deep burns and those that take more than 2 to 3 weeks to heal. Many people with deep burns develop some hypertrophic scarring.
• Tension on the wound: scars across the shoulders, chest, upper arms and over joints are stretched with every movement.
• Delayed healing: infection, wound breakdown or a wound left open longer.
• Surgery: particularly scars that cross skin creases rather than running along them.
• Acne: inflamed cysts on the chest, back and jaw can leave raised scars. See acne scars.
• Piercings, tattoos, vaccinations, scratches and insect bites.
• Age and genetics: more common in children, teenagers and young adults, and in people with darker skin.

How it is diagnosed

Diagnosis is clinical: a doctor looks at the scar, its timing and whether it has stayed within the wound. A biopsy is not usually needed, but is done if a scar changes suddenly, ulcerates or does not look typical, because rare skin cancers can arise in old burn scars (Marjolin ulcer).

Hypertrophic scar treatment

Treatment works best while the scar is still young, red and active. Most plans combine several steps.

First-line treatments

• Silicone gel or silicone sheets: the best-supported first treatment. Apply to closed, healed skin for at least 12 hours a day (sheets) or twice daily (gel) for at least 2 to 3 months. They hydrate the scar and reduce collagen production.
• Pressure therapy: custom compression garments for burns, worn 23 hours a day for 6 to 12 months or longer.
• Massage: firm massage with a plain moisturizer a few times a day helps soften the scar once the wound has fully closed.
• Sun protection: UV exposure darkens young scars. Use clothing or SPF 30+ for at least a year.

Treatments by a doctor

• Corticosteroid injections: triamcinolone injected into the scar every 4 to 6 weeks flattens it and reduces itching. Side effects include thinning of the skin and lighter patches.
• 5-fluorouracil injections: sometimes combined with steroids for stubborn scars.
• Laser: pulsed dye laser reduces redness and itch. Fractional lasers improve texture and stiffness, especially in burn scars.
• Cryotherapy: freezing for small scars, used less in darker skin because it can lighten it.
• Surgery: scar revision, often with techniques such as Z-plasty that change the direction of tension. It is useful for contractures and scars under tension, and is followed by silicone and sometimes steroid injections.

Onion extract gels and vitamin E have little reliable evidence and vitamin E can irritate the skin.

Complications

• Contracture: tightening that restricts the movement of a joint, mostly after burns. It may need surgery and physical therapy.
• Persistent itching or pain.
• Visible scarring that affects confidence, particularly on the face and neck.

Prevention

• Keep wounds clean and moist with petroleum jelly and a covering until healed.
• Get deep or gaping cuts closed promptly by a professional.
• Avoid stretching new scars, for example heavy lifting after chest or shoulder surgery.
• Start silicone as soon as the skin has closed if you scar easily.
• Treat acne early to prevent deep inflamed lesions.

The hypertrophic scarring page looks at the wound-healing process and at-risk procedures in more detail, and the general scar page covers other scar types.

Frequently asked questions

Does a hypertrophic scar go away?

It often improves a lot on its own. Most hypertrophic scars soften, flatten and fade over 12 to 24 months, but they may stay slightly wider or a different color than the surrounding skin. Treatment speeds and improves this.

How do I flatten a hypertrophic scar?

Start with silicone sheets or gel daily for at least 2 to 3 months, plus massage and sun protection. If the scar stays raised, a dermatologist can inject steroids every 4 to 6 weeks, and laser treatment can help redness and texture.

How can I tell if it is a keloid or a hypertrophic scar?

A hypertrophic scar stays within the borders of the original wound, appears within weeks and often flattens over time. A keloid grows beyond the wound into normal skin, can appear months later and rarely goes away by itself. A dermatologist can confirm which one you have.

Can a hypertrophic scar turn into a keloid?

They are different responses, but early on they can look alike. A scar that keeps spreading beyond the wound edges is behaving as a keloid. Telling them apart matters because keloids are more likely to come back after surgery.

What is the bump on my piercing?

A firm bump next to a new nose or ear piercing is usually a hypertrophic scar or an irritation bump. It often shrinks over weeks to months with gentle cleaning, avoiding twisting the jewelry, and silicone. A large, growing lump on the earlobe may be a keloid and needs a dermatologist.