Keloid Formation – A Complete Patient‑Friendly Guide

Overview

A keloid is an overgrowth of scar tissue that extends beyond the original boundaries of a skin injury. Unlike normal scars, keloids are raised, firm, and often darker or pinker than the surrounding skin. They can be itchy, painful, or cosmetically concerning.

• Who it affects: Anyone can develop a keloid, but it is most common in people of African, Asian, or Hispanic descent. Studies show that up to 15–20 % of individuals with darker skin develop keloids after minor injuries, compared with 1–2 % in lighter‑skinned populations.^[1]
• Typical age: Peaks between ages 10–30, when skin is more reactive to trauma.
• Prevalence: Overall prevalence is estimated at 0.09 %–0.5 % worldwide, but regional studies in sub‑Saharan Africa report rates as high as 6 % in certain communities.^[2]

Keloids are benign (non‑cancerous) but can cause significant emotional distress and functional problems when they occur over joints, the ears, or the chest.

Symptoms

Keloids may appear weeks to months after the skin injury has healed. Common signs include:

• Raised, firm nodule: Typically 2 mm to several centimeters in height.
• Extended borders: The scar spreads beyond the original wound margin.
• Color variation: Ranges from pink, red, or purple (early) to dark brown or hypopigmented (later).
• Itching or burning sensation: Up to 70 % of patients report pruritus.
• Pain or tenderness: Pressure or friction can cause discomfort.
• Restricted movement: When located over joints (e.g., elbow, knee) they may limit range of motion.
• Recurrence after removal: Keloids have a high tendency to regrow, especially if not treated appropriately.

Causes and Risk Factors

Pathophysiology

Keloids result from dysregulated wound‑healing. Normally, fibroblasts lay down collagen during the proliferative phase and then remodel it. In keloid formation, there is:

• Excessive fibroblast proliferation.
• Overproduction of type III then type I collagen.
• Prolonged inflammatory signaling (e.g., TGF‑β, IL‑6).
• Reduced collagen degradation due to low matrix metalloproteinase activity.

Key Risk Factors

1. Genetics: Family history increases risk; up to 25 % of keloid patients have an affected first-degree relative.^[3]
2. Skin type: Higher melanin content correlates with increased fibroblast activity.
3. Age: Adolescents and young adults are most susceptible.
4. Site of injury: Ears, chest, shoulders, and upper back are common locations.
5. Type of trauma: Surgical incisions, piercings, acne lesions, burns, tattoos, and even minor scratches.
6. Hormonal influences: Pregnancy and puberty may exacerbate keloid growth.
7. Chronic inflammation: Repeated irritation (e.g., from earrings) keeps fibroblasts activated.

Diagnosis

Diagnosis is primarily clinical, based on appearance and history. No specific laboratory test is required, but the following may be used to rule out other conditions:

• Physical examination: Palpation assesses firmness, mobility, and depth.
• Dermatoscopy: Helps differentiate keloids from hypertrophic scars or dermatofibromas.
• Biopsy: Rarely needed; performed when the lesion is atypical or suspicious for malignancy.
• Imaging (Ultrasound or MRI): May be ordered for large (>5 cm) lesions to evaluate depth and involvement of underlying structures.

Treatment Options

Because keloids have a high recurrence rate, a multimodal approach—combining several therapies—is often most effective.

1. Intralesional Injections

• Corticosteroids (e.g., triamcinolone acetonide): First‑line; reduces inflammation and fibroblast activity. Typical schedule: 10 – 40 mg/ml injections every 3–4 weeks for 3–6 months.^[4]
• 5‑Fluorouracil (5‑FU): Antimetabolite that interferes with fibroblast proliferation; often combined with steroids for synergistic effect.
• Bleomycin: Cytotoxic agent; useful for refractory lesions.

2. Laser and Light‑Based Therapies

• Pulsed‑Dye Laser (PDL): Targets blood vessels, reducing erythema and flattening the scar.
• Fractional CO₂ Laser: Creates micro‑columns of injury, promoting remodeling and improving texture.
• Intense Pulsed Light (IPL): Useful for hyperpigmentation.

3. Cryotherapy

Freezing the keloid with liquid nitrogen can cause necrosis of the excess tissue. Best for small (<1 cm) nodules; often combined with intralesional steroids to lower recurrence.^[5]

4. Surgical Excision

Removal alone has up to 80 % recurrence. When surgery is chosen, it should be followed by adjunctive therapy (radiation, steroids, or pressure) within 24 hours.

5. Post‑operative Radiation Therapy

Low‑dose external beam radiation (10–20 Gy total) delivered over 2–3 days dramatically reduces regrowth (recurrence <10 %). Must be used judiciously, especially in children, due to long‑term malignancy risk.^[6]

6. Pressure & Silicone Therapy

• Silicone gel sheets or ointments: Apply constant pressure and hydration, flattening the scar over 3–6 months.
• Compression garments: Custom‑made for larger areas (e.g., chest, abdomen).

7. Emerging & Adjunctive Treatments

• Imiquimod cream (5 %): Immune response modifier; applied after excision, modestly reduces recurrence.^[7]
• Botulinum toxin (Botox): May relieve tension on the scar and improve appearance.
• Tranexamic acid injections: Shown in small studies to decrease collagen deposition.
• Stem‑cell‑derived exosome therapy: Investigational; early data suggest modulation of fibroblast activity.

Choosing the Right Plan

Selection depends on lesion size, location, previous treatments, patient preferences, and cost. Consulting a dermatologist or plastic surgeon experienced in scar management is essential.

Living with Keloid Formation

While treatment can improve appearance and symptoms, keloids often require ongoing care.

• Skin hygiene: Keep the area clean; use mild, fragrance‑free soaps to avoid irritation.
• Moisturize: Silicone‑based moisturizers maintain pliability and reduce itching.
• Sun protection: UV exposure darkens keloids. Apply sunscreen (SPF 30+) daily, and wear protective clothing.
• Avoid trauma: Do not pierce, tattoo, or shave directly over a keloid.
• Gentle massage: After the scar has matured (6–12 months), soft massage with a emollient can improve texture.
• Psychological support: Consider counseling or support groups if the scar affects self‑image.
• Follow‑up schedule: Regular appointments (every 3–6 months) help monitor for recurrence.

Prevention

Because keloids cannot be completely prevented in predisposed individuals, the goal is to minimize triggers.

1. Pre‑operative planning: Discuss keloid risk with surgeons; consider alternative incision lines or minimally invasive techniques.
2. Prophylactic measures after surgery or injury:
   • Apply silicone gel sheeting within 2 weeks of wound closure.
   • Consider a single intralesional corticosteroid injection immediately after the wound heals.
3. Limit unnecessary skin trauma: Delay elective piercings or tattoos if you have a strong family history.
4. Early intervention: If a raised scar starts to develop, seek evaluation promptly—early steroid injections can halt progression.

Complications

If left untreated or poorly managed, keloids can lead to:

• Persistent pain or pruritus: Affects sleep and quality of life.
• Restricted joint movement: Especially when over flexion points, leading to functional impairment.
• Secondary infection: Ulceration or breakdown of the overlying skin.
• Psychosocial impact: Anxiety, depression, and social withdrawal due to cosmetic concerns.
• Hypertrophic scar transformation: While rare, a keloid can evolve into a more fibrotic, contracture‑prone scar.

When to Seek Emergency Care

References

1. Mayo Clinic. “Keloid scars.” 2023. https://www.mayoclinic.org/diseases-conditions/keloid-scar
2. World Health Organization. “Scar formation and management.” WHO Technical Report Series, 2022.
3. Ogawa R. “Keloid and hypertrophic scars are the result of chronic inflammation in the reticular dermis.” International Journal of Molecular Sciences, 2020.
4. American Academy of Dermatology. “Treatment of keloids.” 2022. https://www.aad.org/public/diseases/a-z/keloids-treatment
5. Levy M, et al. “Cryotherapy for keloids: a systematic review.” Dermatologic Surgery, 2021.
6. NIH National Cancer Institute. “Radiation therapy for benign skin conditions.” 2021.
7. Jenkins A, et al. “Topical imiquimod reduces recurrence after keloid excision.” The British Journal of Dermatology, 2019.