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PATHOLOGICAL SCARS

Overview

  • Umbrella term for hypertrophic and keloid scars

  • Hypertrophic scars

    • Excessive cutaneous scar formation which is contained within the borders of the original wound

    • Primarily type III collagen orientated parallel to epidermal surface with abundant myofibroblasts and extracellular collagen​

    • Predisposition in wounds closed under tension or on flexor surfaces

  • Keloid scars​

    • Excessive cutaneous scar formation which extends outside the borders of the original wound

    • Disorganised type I and III collagen

    • Only seen in humans, rare in newborns or elderly

    • Genetic and endocrine influences

    • Rarely regress and more resistant to excision and therapy

Overview

Treatment of hypertrophic scar

  • Silicone gel sheeting

    • Prevent hypertrophic scar formation and accelerate involution​

    • Mechanism of action unknown

      • Increased hydration from occlusion leading to decrease in inflammatory cytokines​

      • Direct effect by silicone particles and increase in static electrical fields

  • Compression garments​​

    • Used since 1970s but has weak evidence

    • Marginal improvements of questionable clinical significance in scar thickness​

  • Intralesional corticosteroid injection​

    • Second line therapy of hypertrophic scars refractory to silicone gel sheeting​

    • Mechanism of action unknown

      • Focal suppression of inflammatory cytokines and inhibition of fibroblast proliferation​

    • Local side effects

      • Pain​

      • Skin atrophy

      • Telangiectasias

      • Dyspigmentations

  • Pulse-dye laser

    • Mechanism of action unknown​

      • Absorption by haemoglobin with capillary ablation and reduced perfusion​

    • Evidence is weak​

Treatment of hypertrophic scar

Treatment of keloid scar

  • No uniformly successful treatment

  • Risk of recurrence should be discussed with patient prior to treatment, and appropriate goals must be set

  • Intralesional steroid injection

    • First line in treatment​

    • Synergistic benefit of other modalities

    • Triamcinolone acetonide 10 mg/ml, and if no response 40mg/ml

    • Painful

    • Response best in early rapidly proliferating lesions

  • Low-dose radiotherapy​

    • 20 Gy​ immediately after excision

    • Risks include potential for malignant transformation

  • Cryotherapy​

    • Low-cost and effective in selected keloid scars​

    • Mechanism unknown

    • Effects synergistic with steroid injection

    • Side effects

      • Pain​

      • Blistering

      • Lengthy wound healing

      • Skin atrophy

      • Dyspigmentation

Treatment of keloid scar
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