Keloid

Aka: Keloid, Hypertrophic Scar Management

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II. Definitions

  1. Keloid
    1. Derived from Greek "cheloides" or crab's claw
    2. Firm, Rubbery Nodules that proliferate in the first year of Skin Injury

III. Epidemiology

  1. More common in black, asian or hispanic patients (Keloids)
    1. Confers >15 fold increased risk
  2. Familial predisposition
    1. One third of Keloid patients have a first degree family member with Keloids
  3. Most common onset age 10 to 30 years old

IV. Pathophysiology

  1. Excessive fibrous repair response to Skin Injury and chronic inflammation in the reticular Dermis
    1. Excessive fibroproliferative Collagen response and failed inhibition of inflammatory Proteins
    2. Results in a scar formed from disorganized extracellular matrix
    3. Inflammation continues without spontaneous regression (in contrast to Hypertrophic Scar)
  2. Overgrowth of scar tissue at sites of Trauma (acne, Burn Injury, surgery, Ear Piercing, Tattoo or Skin Infection)
    1. Extension of lesion beyond Skin Injury site
    2. Onset 3 to 12 months after wound and tend to worsen overtime, maintaining depth>4 mm
    3. Contrast with Hypertrophic Scar which is immediate, localized to the wound, superficial and regresses over time

V. Risk Factors

  1. Dark skin as noted above
  2. Delayed healing (longer than 3 weeks)
  3. Burn Injury (among the highest risk for Keloid formation)
  4. Severe acne
  5. Ear Piercing
  6. Varicella Vaccination
  7. Female gender
  8. Pregnancy
  9. Obesity
  10. Genetic Syndromes
    1. Autosomal Dominant inherited condition (5-10% familial cases)
    2. Goeminne Syndrome
    3. Rubinstein-Taybi Syndrome

VI. Symptoms

  1. May be asymptomatic
  2. Pruritus
  3. Pain or Hypersensitivity

VII. Signs: Keloids

  1. Characteristics
    1. Firm, smooth, shiny, Skin-Colored Papules, Nodules, Plaques at or near prior Skin Injury
    2. Start as red or pink and become hyperpigmented later
  2. Distribution: Regions of high dermal tension
    1. Sternum or chest
    2. Lower Abdomen
    3. Upper arms
    4. Nape of neck or back
    5. Scalp
    6. Ear Pinna
    7. Cheeks and jaw line
    8. Major Joints

VIII. Differential Diagnosis

  1. Hypertrophic Scar
    1. Keloids, in contrast, grow beyond original injury margins and do not regress spontaneously with time
  2. Acne Keloidalis Nuchae
  3. Dermatofibroma
  4. Dermatofibrosarcoma Protuberans
  5. Giant Cell Fibroblastoma
  6. Keloidal Basal Cell Carcinoma
  7. Neurofibroma (in Neurofibromatosis)
  8. Desmoid tumor
  9. Scleroderma
  10. Scar Sarcoidosis
  11. Foreign Body Granuloma

IX. Labs

  1. Biopsy Findings (if biopsied for other reasons)
    1. Whorls and Nodules
    2. Thick Collagen bundles irregularly scattered throughout the Dermis

X. Course

  1. May continue to enlarge for years
    1. Contrast with Hypertrophic Scar which regresses over time

XI. Management: First-Line therapy

  1. General
    1. Newer lesions are most susceptible to treatment (treat early)
  2. Intralesional Corticosteroid Injection
    1. Consider combining injection with Cryotherapy, laser, Fluorouracil or surgery
    2. Adverse effects include local skin atrophy, dyspigmentation, Telangiectasias
    3. First-line treatment with scar regression in >50%, but recurrence in 50% of cases
    4. Triamcinolone Acetonide (10 mg/ml up to 40 mg/ml)
      1. Dilute in 3 cc Lidocaine 1%
      2. Repeat injection monthly until improvement (typically 2-3, up to 6 injections)
      3. Inject only into lesions (avoid atrophy in surrounding skin)
  3. Fluorouracil
    1. Adjunct to intralesional Corticosteroid Injection
    2. Apply topical weekly to biweekly for 6 to 8 weeks
    3. Khan (2014) J PAK Med Assoc 64(9): 1003-7 [PubMed]
    4. Jiang (2020) Aesthetic Plast Surg 44(5): 1859-68 [PubMed]
  4. Cryotherapy (Liquid Nitrogen)
    1. Spray Liquid Nitrogen (topical)
      1. Perform every 2 to 4 up to 20 sessions total
    2. Intralesional Liquid Nitrogen Injection
      1. Injected directly into lesionss every 2 to 3 weeks is more effective than spray
      2. Mourad (2016) J Dermatolog Treat 27(3): 264-9 [PubMed]
    3. May be adjunct to Corticosteroid
      1. Lightly freeze hard Keloid before injection (may soften the lesion)
  5. Silicone Elastomer Sheeting (e.g. Kelo-cote, ScarAway)
    1. Applied to closed wound site for 12-24 hours over everyday for 2-3 months
    2. Use gels on the face and extensor surfaces (knees and elbows) and sheets on larger flat areas of closed skin

XII. Management: Refractory after one year

  1. Surgical Excision
    1. Not recommended as first-line therapy due to very high recurrence rate after excision (>50%)
    2. Perform surgery with tension reducing techniques (e.g. W-plasty, Z-Plasty)
    3. Combine surgical excision with adjunctive measures
      1. Corticosteroid Injection
        1. Protocol 1: Injection at 10-14 days excision
          1. Zhang (2024) Aesthetic Plastic Surg 48(15): 2927-40 [PubMed]
        2. Protocol 2: Serial Injections
          1. First injection at time of excision then
          2. Reinject weekly for 3-5 weeks, then
          3. Reinject monthly for 3-6 months
      2. Consider also applying Silicone Elastomer Sheeting
      3. Consider applying Imiquimod 5% cream (Aldara) on alternate nights for 8 weeks after surgery
        1. More effective in low skin tension areas such as ear lobes
        2. Chuangsuwanich (2007) J Med Assoc Thai 90(7):1363-7 [PubMed]
  2. Other measures
    1. Pulsed dye laser
    2. Intralesional Verapamil (2.5 mg/ml) in combination with Silicone Elastomer Sheeting
    3. Intralesional Fluorouracil (50 mg/ml) injected 2-3 times weekly
    4. Intralesional Bleomycin (1.5 IU/ml, 0.1 ml) injected on up to 6 consecutive sessions
    5. Intralesional Interferon Alfa-2B 1.5 Million IU twice daily for 4 days
    6. Intralesional OnabotulinumtoxinA Injection 2 to 5 units/site
      1. Ismail (2021) Arch Dermatol Res 313(7): 549-56 [PubMed]
      2. Fu (2022) J Cosmet Dermatol 21(1): 176-90 [PubMed]
    7. Radiation Therapy
      1. Ogawa (2016) J Nippon 83(2): 46-53 [PubMed]
      2. Mankowski (2017) Ann Plast Surg 78(4): 403-11 [PubMed]
  3. References
    1. Atiyah (2007) Aesthetic Plast Surg 31(5): 468-92 [PubMed]

XIII. Prognosis

  1. Factors predicting severe Keloid progression
    1. Local infection (e.g. Chicken Pox)
    2. Lower income
    3. Comorbid rheumatic disorders
    4. Multiple Keloids with wider distribution
    5. Keloids present >15 years
    6. Keloids in high skin tension regions
    7. Liu (2022) Chin Med J 135(7): 828-36 [PubMed]

XIV. Prevention

  1. Post-surgical prophylaxis
    1. Compression Bandage application (pressure dressing applied by wound care)
      1. Applied at 15 to 25 mmHg
      2. Reduces local inflammatory Cytokines with decreased Collagen deposition and scar formation
      3. Consider in Burn Injury and Hypertrophic Scars
    2. Intralesional Triamcinolone (see protocol above)
      1. May be combined with Topical Corticosteroid (e.g. Triamcinolone) applied twice daily
    3. Corticosteroid impregnated tape or plaster (e.g. Cordran Tape, Flurandrenolide)
      1. Applied daily starting 2-3 weeks after Sutures removed, and continued for 3 months postop
      2. Trim sheeting every 24 to 48 hours to size of wound
      3. Avoid extended use (risk of skin atrophy)
    4. Postexcisional Imiquimod 5% cream (Aldara)
      1. Klotz (2020) Wound Repair Regen 28(1): 145-56 [PubMed]
    5. Radiotherapy
      1. Mankowski (2017) Ann Plast Surg 78(4): 403-11 [PubMed]
    6. Reduce postoperative skin tension (e.g. paper tape)
    7. Imiquimod
      1. Sidgwick (2015) Arch Dermatol Res 307(6): 461-77 [PubMed]
    8. Silicon gel sheeting (or hydrocolloid sheeting)
      1. Applied for 6 weeks, starting 2 weeks after surgery or injury
      2. Reduces wound tension, and allows for increased water retention during healing
      3. O'Brien (2013) Cochrane Database Syst Rev 2013(9):CD003826 +PMID: 24030657 [PubMed]
  2. Avoid Ear Piercings and other unnecessary procedures in those with Keloid or scar risk
    1. Preoperative discussion regarding extensive scarring risk
  3. Keep new wounds moist, clean and at rest
    1. Wash new wounds with soap and water, and irrigate under the water tap
    2. Apply non-AntibioticEmollient (e.g. petrolatum, Aquaphor)
    3. Apply cover bandage
    4. Avoid excessive movement and Stretching of the skin at new wound sites or following procedures
    5. Early skin grafting of full thickness Burn Injury
  4. Avoid topical irritants
    1. Neosporin (Contact Dermatitis risk)
    2. Vitamin E Capsules (local irritation, and no benefit for Wound Healing)
  5. Wound closure techniques have similar scarring results (Dermabond vs Sutured closure)
  6. Silicone Elastomer Sheeting (e.g. Kelo-cote)
    1. Apply after Wound Healing (typically 3-4 weeks after onset)
  7. Measures not found effective in preventing Keloids
    1. Scar massage (however may reduce short-term initial pain and Pruritus)

XV. References

  1. Atiyah (2007) Aesthetic Plast Surg 31(5): 468-92 [PubMed]
  2. Bailey (2024) Am Fam Physician 110(6): 605-11 [PubMed]
  3. Brissett (2001) Facial Plast Surg 17(4): 263-72 [PubMed]
  4. Frazier (2023) Am Fam Physician 107(1): 26-34 [PubMed]
  5. Juckett (2010) Am Fam Physician 80(3): 253-60 [PubMed]
  6. Leventhal (2006) Arch Facial Plast Surg 8(6): 362-8 [PubMed]
  7. Sherris (1995) Otolaryngol Clin North Am 28(5): 1057-68 [PubMed]

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