II. Definition

  1. Keloid
    1. Derived from Greek "cheloides" or crab's claw

III. Pathophysiology

  1. Excessive fibrous repair response to Skin Injury
  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 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

IV. Epidemiology

  1. More common in black, asian or hispanic patients (Keloids)
    1. Confers >15 fold increased risk
  2. Most common onset age 10 to 30 years old

V. Risk Factors

  1. Dark skin as noted above
  2. Delayed healing (longer than 3 weeks)
  3. Burn Injury
  4. Severe acne
  5. Ear Piercing
  6. Varicella Vaccination

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
    1. Sternum or chest
    2. Upper arms
    3. Nape of neck or back
    4. Scalp
    5. Ear Pinna
    6. Cheeks and jaw line

VIII. Differential Diagnosis

IX. Course

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

X. Management: First-Line therapy

  1. Intralesional Corticosteroid Injection
    1. Consider combining injection with Cryotherapy pretreatment below
    2. Triamcinolone Acetonide 10 mg/ml
      1. Dilute in 3 cc Lidocaine 1%
      2. Repeat injection monthly until improvement (typically 2-3 injections)
  2. Cryotherapy
    1. May be adjunct to Corticosteroid
    2. Lightly freeze hard Keloid before injection (may soften the lesion)
  3. 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

XI. Management: Refractory after one year

  1. Surgical Excision
    1. Not recommended as first-line therapy due to very high recurrence rate after excision
    2. Combine surgical excision with adjunctive measures
      1. Corticosteroid Injection
        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
  3. References
    1. Atiyah (2007) Aesthetic Plast Surg 31(5): 468-92 [PubMed]

XII. Prevention

  1. 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-antibiotic Emollient (e.g. petrolatum, Aquaphor)
    3. Apply cover bandage
    4. Avoid excessive movement and Stretching of the skin at new wound sites or following procedures
  2. Avoid topical irritants
    1. Neosporin (Contact Dermatitis risk)
    2. Vitamin E Capsules (local irritation, and no benefit for Wound Healing)
  3. Avoid Ear Piercings and other unnecessary procedures in those with Keloid or scar risk
  4. Wound closure techniques have similar scarring results (Dermabond vs Sutured closure)
  5. Silicone Elastomer Sheeting (e.g. Kelo-cote)
    1. Apply after Wound Healing (typically 3-4 weeks after onset)

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Related Studies

Ontology: Keloid (C0022548)

Definition (NCI) An irregularly shaped, elevated mark on the skin caused by deposits of excessive amounts of collagen during wound healing. It extends beyond the original boundaries of the wound and may enlarge progressively.(NICHD)
Definition (NCI_NCI-GLOSS) A thick, irregular scar caused by excessive tissue growth at the site of an incision or wound.
Definition (MSH) A sharply elevated, irregularly shaped, progressively enlarging scar resulting from formation of excessive amounts of collagen in the dermis during connective tissue repair. It is differentiated from a hypertrophic scar (CICATRIX, HYPERTROPHIC) in that the former does not spread to surrounding tissues.
Definition (CSP) progressively enlarging scar resulting from formation of excessive amounts of collagen in the dermis during connective tissue repair; spreads to surrounding tissues.
Concepts Acquired Abnormality (T020)
MSH D007627
ICD9 701.4
ICD10 L91.0
SnomedCT 33659008, 156393003, 58405006
English Keloid, keloid skin disorder, KELOID, Keloid scar of skin, keloid scar (diagnosis), keloid scar, Keloid [Disease/Finding], keloid scarring, keloid, keloids scars, keloid skin, keloid scars, keloids, cheloids, keloids skin, scar keloid, Keloids, Keloid scar, Cheloid, Cheloid of skin, Keloid of skin, Keloid cicatrix, Keloid (morphologic abnormality), Keloid scar (disorder), cheloid, keloid; scar, scar; keloid
French CHELOIDE, Cicatrice chéloïde, Chéloïde
Portuguese QUELOIDE, Queloide, Quelóide
Spanish QUELOIDE, cicatriz queloide, cicatriz queloide (trastorno), cicatriz queloide de la piel, cicatriz queloide de la piel (trastorno), cicatriz queloide cutánea, queloide (anomalía morfológica), queloide cutáneo, queloide de la piel, queloide, Cicatriz queloide, Queloide
German KELOID, Keloidnarbe, Keloid, Narbenkeloid
Italian Cicatrici cheloidee, Cheloide
Dutch keloïd, keloïd; litteken, litteken; keloïd, Keloïdlitteken, keloïdlitteken, Keloïd
Japanese ケロイド瘢痕, ケロイド, ケロイドハンコン, ケロイド
Swedish Ärrsvulst
Czech keloid, Keloidní jizva, Keloid
Finnish Keloidi
Korean 켈로이드성 흉터
Croatian KELOID
Latvian Keloīds
Polish Bliznowiec, Keloid
Hungarian Keloid, Heg keloid
Norwegian Keloid