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Wound healing, scars and chronic wounds
Wound healing passes through four phases — haemostasis, inflammation, proliferation and remodelling; diabetes, smoking, steroids, malnutrition, infection and radiation delay it, and in a chronic wound the cause (venous, arterial, neuropathic) is sought rather than just changing dressings.
Why it matters in the exam
Basic questions test the phases of healing and the key cells in each: neutrophils in the first days, then the macrophage — the most important cell of the inflammatory phase, which directs the transition to proliferation; in the proliferative phase fibroblasts produce type III collagen, granulation tissue and new vessels form, and the skin closes; in remodelling type I collagen gradually takes the place of type III and strength rises over months — but never returns to the original strength.
Candidates are also asked about what impairs healing: diabetes, smoking, steroids (vitamin A can reverse part of the effect), malnutrition (protein, vitamin C and zinc), infection, radiation, hypoxia and chemotherapy. For scars — a hypertrophic scar stays within the wound borders and improves with time, while a keloid extends beyond them, is common in dark skin and recurs after simple excision; so steroid injection, silicone and sometimes radiotherapy are combined. For a chronic leg wound, distinguish a venous ulcer (above the medial malleolus, compression), an arterial ulcer (toes, pain, low ABI — revascularisation) and a neuropathic diabetic ulcer (sole of the foot, offloading).
Key points
- Four phases: haemostasis, inflammation, proliferation, remodelling.
- The macrophage — the key cell of inflammation; collagen III is replaced by I.
- Impairments: diabetes, smoking, steroids, malnutrition, infection, radiation.
- Hypertrophic — within the wound borders; keloid — beyond them and recurs.
- Venous ulcer — compression; arterial — revascularisation; neuropathic — offloading.
Summary table
| Topic | Details | Exam note |
|---|---|---|
| Inflammatory phase | Days 1–4: neutrophils, then macrophages | The macrophage is the most important cell in this phase |
| Proliferative phase | From day 4 to about 3 weeks: fibroblasts, collagen III, granulation, new vessels | Vitamin C is needed for collagen synthesis |
| Remodelling phase | From 3 weeks to a year: collagen III replaced by I | Strength never returns to the original |
| Impairments of healing | Diabetes, smoking, steroids, malnutrition, infection, radiation, hypoxia | Vitamin A reduces the effect of steroids |
| Hypertrophic scar versus keloid | Hypertrophic — within the wound borders and improves; keloid — extends beyond and rarely improves | A keloid recurs after simple excision — add steroid, silicone or radiotherapy |
| Chronic leg ulcer | Venous — above the medial malleolus; arterial — toes, pain; neuropathic — sole of the foot | Venous — compression; arterial — revascularisation; neuropathic — offloading |
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Sources
- Sabiston Textbook of Surgery, 21st edition (2022) — Wound Healing
- Schwartz's Principles of Surgery, 11th edition (2019) — Wound Healing
- International consensus on the management of keloids and hypertrophic scars (Ogawa), 2020 — Prevention and treatment
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-02. The text may contain errors; when in doubt, check the source.