Keloid Scars: Causes, Prevention & Treatment Options

What Are Keloid Scars?

A keloid is an abnormal, raised overgrowth of scar tissue that extends beyond the original boundary of a skin wound. Where a normal scar stays within the injury site and gradually flattens over months, a keloid keeps growing — expanding laterally into surrounding uninjured skin and thickening upward from the skin surface. Keloids can continue growing for months to years.

Keloids are classified as benign fibroproliferative lesions. They are not cancerous, do not spread internally, and carry no systemic health risk — but they can cause significant symptoms including pain, itching, tightness, and cosmetic distress, particularly when they form over joints or on visible areas like the face, chest, or earlobes.

They should be distinguished from hypertrophic scars, which are also raised and firm but remain confined to the original wound margin and tend to flatten with time. Both conditions are now understood to exist on a spectrum of the same pathological process — chronic inflammation in the reticular dermis — with keloids representing the more severe, strongly inflamed end.

How Keloids Form: The Pathophysiology

Normal wound healing passes through overlapping phases: hemostasis, inflammation, proliferation, and remodeling. In keloid-prone individuals, this process derails at the remodeling phase. The inflammatory phase persists abnormally, driven by upregulation of pro-inflammatory cytokines including IL-1α, IL-1β, IL-6, and tumor necrosis factor-α.

This chronic inflammation signals dermal fibroblasts to overproduce collagen — particularly Type I and Type III collagen — at rates that far exceed what is needed to close the wound. The resulting dense, disorganized collagen matrix extends beyond the original injury site in every direction. Importantly, the injury must reach the reticular dermis (the deep layer) to trigger this response — purely superficial injuries that stay within the epidermis or papillary dermis do not produce keloids or hypertrophic scars.

Elevated estrogen, androgen, and glucocorticoid receptor expression has been identified in keloid tissue — explaining why hormonal states (pregnancy, puberty) can aggravate keloid formation and growth.

Who Is at Risk?

Skin Tone and Ethnicity

Keloid susceptibility has a pronounced racial pattern. Published epidemiological data show:

• African descent: 5–10% prevalence
• Asian descent: 0.1–1% prevalence
• European/North American (lighter skin): Less than 0.1% prevalence

In the United States, keloids are significantly more common in Black and Latin Americans. Researchers are investigating whether melanocyte concentration or melanin itself plays a mechanistic role — keloids preferentially form on body sites with higher melanocyte density.

Age

Keloid development peaks between ages 10 and 30. They are rare before puberty in individuals without a strong family history, and incidence declines significantly after age 30 in most people, though known keloid-formers remain at risk throughout life.

Family History

Approximately one-third of keloid patients have a first-degree relative (parent or sibling) with keloids. A strong family history — particularly if a parent had severe or multiple keloids — is the single most predictive risk factor.

Triggering Events

Any injury to the deep dermis can trigger a keloid in predisposed individuals. Common triggers identified by the AAD include:

• Body piercings (ear cartilage piercings carry especially high risk)
• Acne (particularly inflammatory nodules and cysts)
• Chickenpox and other infections that scar
• Burns
• Surgical incisions
• Vaccinations (the deltoid/upper arm injection site is a common location)
• Lacerations and abrasions
• Tattoos

Spontaneous keloids — developing without any identifiable injury — are rare but documented.

Signs and Symptoms

Keloids are clinically recognizable by several characteristic features:

• Extension beyond wound margins — the defining feature that distinguishes them from hypertrophic scars
• Raised, firm, rubbery texture — often described as "shiny" or "smooth" on the surface
• Color variation — pink, red, or purple in early stages; brown to hyperpigmented in older lesions
• Size range — from a few millimeters to many centimeters; large keloids on the chest and back are not uncommon
• Symptoms — itching (pruritus) is very common and can be severe; pain and tenderness, particularly with friction; a sensation of tightness or pulling
• Continued growth — unlike hypertrophic scars, keloids do not spontaneously regress and may continue expanding for months to years

Common anatomical locations include earlobes, jawline, chest (particularly the sternum), upper back and shoulders, and upper arms (post-vaccination). The face, palms, and soles are relatively spared.

Treatment Options

No single treatment reliably eliminates keloids permanently. The AAD states plainly that "no treatment can consistently get rid of a keloid." The goal of treatment is reduction in size, symptoms, and appearance — with the understanding that recurrence management is likely to be a long-term commitment in predisposed individuals.

Combining two or more treatments consistently outperforms any monotherapy.

Intralesional Corticosteroid Injection (First-Line)

Intralesional injection of triamcinolone acetonide (TAC) at 2.5–40 mg per site is the most established first-line treatment. The AAD reports that 50–80% of keloids shrink following injection. Injections are typically given in a series (every 4–6 weeks), with softening and flattening occurring between sessions. Side effects include skin atrophy, telangiectasia, and hypopigmentation at the injection site — particularly in darker skin tones.

Recurrence within 5 years is common with corticosteroid injection alone, and the AAD notes this explicitly. Adding a second agent improves durability.

Corticosteroid + 5-Fluorouracil (5-FU) Combination

Intralesional TAC combined with 5-fluorouracil — an antimetabolite that inhibits fibroblast proliferation — outperforms corticosteroid monotherapy. Published meta-analysis data show cure rates of approximately 69.8% for TAC + 5-FU compared to 26.7% for TAC alone. This combination is increasingly considered standard over monotherapy for established keloids.

TAC + Botulinum Toxin A

Meta-analysis data show TAC combined with botulinum toxin A achieves approximately 82.2% cure rates — the highest single combination in published data, though absolute patient numbers in these studies remain modest. The proposed mechanism is that BTX-A reduces mechanical tension on the wound edges by relaxing surrounding muscle, thereby reducing the stimulus for collagen overproduction.

Silicone Gel Sheeting and Gel

Silicone sheeting is the best-evidenced preventive measure and is also used as an adjunct treatment after procedures. A meta-analysis of 20 trials found silicone gel sheets may prevent keloid formation in susceptible patients with newly healed wounds. For established keloids post-surgery, the AAD recommends patients wear pressure garments or silicone devices for 12 to 20 hours a day for several months.

The quality of evidence for silicone is limited — trials have generally been small and methodologically heterogeneous — but the excellent safety profile makes it a low-risk first measure.

Surgical Excision

Surgery alone has a recurrence rate of 45–100% and is therefore rarely used as monotherapy. The wound produced by excision can itself trigger a new, potentially larger keloid at the same site. Surgical excision is reserved as part of a multimodal protocol, almost always combined with immediate post-operative adjuvant therapy.

Surgery + post-operative radiotherapy reduces recurrence to approximately 22% in published series; at specialized centers using optimized protocols, recurrence has been reported below 10%. Surgery is a viable option for large, symptomatic keloids that have failed conservative treatment — but only when combined with adjuvant therapy.

Radiation Therapy

Superficial radiotherapy delivered post-surgically to the wound site before keloid tissue can re-establish is an effective adjuvant. Protocols vary; the maximal biologically effective dose in current use is approximately 30 Gy, with body-site-specific protocols using 18 Gy for high-recurrence areas. Radiation concerns (particularly in younger patients) mean it is reserved for large, recurrent, or treatment-resistant keloids, and typically requires specialist oncology or dermatology collaboration.

Laser Therapy

Pulsed-dye laser (PDL) targets the vascular component of keloids — reducing erythema, pruritus, and height by coagulating feeding vessels. It works best on red, early keloids and is commonly combined with intralesional injections.

Fractional CO2 laser has not demonstrated benefit for keloids in systematic review (in contrast to its efficacy for hypertrophic scars and stretch marks). Nd:YAG laser has shown efficacy for symptom reduction in some studies.

Cryotherapy

Liquid nitrogen cryotherapy can reduce keloid hardness and size, particularly in smaller lesions. It works best as part of a combination protocol. A significant limitation: cryotherapy can cause permanent hypopigmentation in darker skin tones, which limits its use in patients who are already disproportionately affected by keloids.

Pressure Therapy

Sustained mechanical compression — using custom pressure garments (15–25 mmHg), silicone sheets, or specialized earlobe clips post-piercing — reduces blood flow to the keloid and inhibits collagen deposition. Consistent evidence shows it reduces burn scar thickness and hardness. Compliance is the primary challenge, as garments must be worn near-continuously for months.

Prevention: What Evidence Supports

For people who are known to be keloid-prone, the following strategies reduce risk:

1. Apply medical-grade silicone gel or sheeting immediately once any wound has scabbed over — do not wait for a keloid to appear. This is the best-evidenced preventive intervention.
2. Treat acne early and aggressively — inflammatory acne nodules and cysts are a common keloid trigger. AAD explicitly recommends earlier acne treatment in keloid-prone individuals.
3. Avoid elective piercings, particularly ear cartilage piercings — these are among the highest-risk triggers for earlobe and cartilage keloids. If piercings are chosen, immediately apply pressure earrings post-procedure and monitor closely.
4. Inform surgeons and injectors of your keloid history before any procedure, so they can use tension-reducing sutures, minimize wound trauma, and plan adjuvant therapy.
5. Optimize wound care: Keep fresh wounds moist, avoid picking, and protect from sun exposure — UV can stimulate pigmentary changes in healing tissue.
6. Paper tape fixation applied along surgical incisions has been shown in one study to reduce hypertrophic scar risk after caesarean section by 13.6-fold.

Keloids vs. Hypertrophic Scars: Key Differences

Both conditions are currently understood as existing on a spectrum of pathological dermal inflammation, rather than as entirely distinct entities.

When to See a Dermatologist

See a dermatologist promptly if:

• A raised, growing scar is developing beyond the wound boundary — early treatment produces better outcomes than waiting for the keloid to fully establish
• A previous keloid is returning after treatment
• Any scar is causing significant pain, itching, or functional limitation (for example, restricting joint movement)
• You are planning any elective procedure (piercing, surgery, tattoo) and have a personal or family history of keloids — pre-emptive adjuvant planning is far more effective than treating an established keloid
• Keloids are causing significant psychological distress or affecting quality of life

Do not attempt to excise or aggressively treat a keloid at home — attempts to remove or drain keloid tissue without appropriate adjuvant management will almost certainly cause a larger recurrence.