Keloid

Aka: Keloid, Hypertrophic Scar

1. Definition
   1. General
      1. Excessive fibrous repair response to skin injury
   2. Hypertrophic Scar
      1. Isolated to site of skin injury
      2. Can occur anywhere, but have a predilection for extensor surfaces
      3. Onset within 1 month of wound and regress and flatten with time
   3. Keloid (derived from Greek "cheloides" or crab's claw)
      1. Extension of lesion beyond skin injury site
      2. Typically on Sternum, upper arms, Ear Pinna and cheeks
      3. Onset >3 months after wound and tend to worsen overtime, maintaining depth>4 mm
2. Epidemiology
   1. More common in African-American descent or other dark skin (Keloids)
      1. Confers >15 fold increased risk
   2. Most common onset over age 30 years
3. Risk Factors
   1. Dark skin as noted above (Keloids)
   2. Delayed healing (longer than 3 weeks)
   3. Burn Injury
   4. Severe acne
   5. Ear Piercing
   6. Varicella vaccination
4. Pathophysiology: Stages
   1. Stage 1: Inflammation occurs for up to first 10 days
   2. Stage 2: Proliferation occurs over next 14 days
   3. Stage 3: Maturation and remodeling may continue for years
5. Signs
   1. Firm Papules or Nodules at or near prior skin injury
6. Differential Diagnosis
   1. Dermatofibroma
   2. Dermatofibrosarcoma protuberans
   3. Desmoid tumor
   4. Scar Sarcoidosis
   5. Foreign body granuloma
7. Course
   1. Hypertrophic Scar
      1. Regress over time
   2. Keloid
      1. May continue to enlarge for years
8. 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
9. 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
   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
10. Prevention
    1. Keep new wounds moist and clean
       1. Apply non-antibiotic Emollient (e.g. petrolatum, Aquaphor)
       2. Apply cover bandage
    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)
11. References
    1. Atiyah (2007) Aesthetic Plast Surg 31(5): 468-92
    2. Brissett (2001) Facial Plast Surg 17(4): 263-72
    3. Juckett (2010) Am Fam Physician 80(3): 253-60
    4. Leventhal (2006) Arch Facial Plast Surg 8(6): 362-8
    5. Sherris (1995) Otolaryngol Clin North Am 28(5): 1057-68