Wound Healing

  1. Normal healing (3R's)

    1. Reaction: inflammatory process (72 hours)
    2. Regeneration: proliferation (up to three weeks)
    3. Remodeling: (three weeks to two years)
  2. Black wound: most often in late reaction or early regeneration phase

    1. Macrophages are migrating to injury to clean up bacteria and debris
    2. Growth factors stimulating new vascular growth at wound base (angiogenesis), fibroblast migration and fibroblast proliferation
    3. Collagen being deposited, filling wound with scar tissue
    4. If eschar left intact and kept dry:
      • cellular debris will escape wound edges as necrotic tissue begins to separate from granulation tissue
      • usually only inflamed around edges
    5. If eschar becomes contaminated:
      • becomes excellent medium for infection
      • wound remains in reaction or inflammatory stage
      • systemic signs of infection
    6. Eschar delays regeneration phase by interfering with cell migration and wound closure
    7. Risk of wound infection increases as the amount of necrotic tissue increases
    8. Needs debridement

    Black Eschar


  3. Yellow wound (yellow necrosis or slough): tissue not damaged enough to form an eschar so wound covered with thick yellow fibrous debris or viscous exudate

    1. Usually in late reaction or early regeneration
    2. High risk of infection due to excellent medium for bacterial growth
    3. Regeneration phase continuing with earlier wound contraction than with the thick eschar
    4. Needs continuing debridement


  4. Red wound: if chronic usually in late regeneration or remodeling phase. Red indicates presence of granulation tissue.

    1. Color of granulation tissue affected by nutritional status and blood supply
      • full thickness ulcer: crater with pale pink to beefy red granulation tissue
      • crater slowly fills with granulation tissue from bottom upward
    2. Wound contraction and epithelialization continues. Epithelialization occurs from wound edges inward.