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Hypertrophic scar, keloid and scar revision
A hypertrophic scar stays within the wound's borders and tends to regress over time, whereas a keloid extends beyond the wound, does not regress and recurs almost always after excision alone — so keloid excision needs adjuvant treatment, such as steroid or radiation.
Why it matters in the exam
A hypertrophic scar appears within weeks, in areas under tension or over joints, and under the microscope contains type 3 collagen fibres parallel to the skin surface and nodules with myofibroblasts. A keloid can appear months after injury, even after a minor one (earring, acne), on the ear, anterior chest and shoulders, is commoner in dark skin and in families, and under the microscope shows thick, disorganised collagen bundles. Excision alone of a keloid leads to recurrence in most cases. First-line treatment: silicone sheets or gel (also for prevention), pressure garments (for burn scars, nearly all day for months), and intralesional triamcinolone every 4 to 6 weeks, alone or with 5-FU. When a keloid is excised, steroid injections or radiation within 24 to 48 hours are added.
The Vancouver scar scale assesses four components: pigmentation, vascularity (colour), pliability and height — and does not include pain or itch. Pulsed dye laser reduces redness. Scar revision is done after the scar matures, usually after 12 months. Z-plasty lengthens the scar and turns its direction to the natural tension lines: at 60 degrees about 75% lengthening is gained, at 45 — about 50%, and at 30 — about 25%. W-plasty or a "geometric broken line" breaks up a long straight scar on a flat surface so that it is less conspicuous, but they do not lengthen it. Incisions are planned along the skin tension lines (Langer lines or RSTL).
Key points
- Hypertrophic — within borders; keloid — beyond them.
- Keloid: excision only with steroid or radiation.
- Silicone and pressure — prevention and first-line treatment.
- Vancouver: pigmentation, vascularity, pliability, height.
- Z-plasty 60 degrees — about 75% lengthening.
Summary table
| Feature | Hypertrophic scar | Keloid |
|---|---|---|
| Borders | Within the wound borders | Extends beyond the borders |
| Timing and course | Weeks; partial regression | Months; does not regress |
| Typical site | Over joints, tension areas, burns | Ear, anterior chest, shoulders |
| Histology | Parallel type 3 collagen, nodules with myofibroblasts | Thick disorganised collagen bundles |
| Treatment | Silicone, pressure, steroid, laser | Steroid; excision only with steroid or radiation |
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Sources
- International Advisory Panel on Scar Management: updated international clinical recommendations, 2014 — Prevention and treatment of hypertrophic scars and keloids
- Japan Scar Workshop Consensus Document, 2018 — Keloid and hypertrophic scar treatment algorithm
- Grabb and Smith's Plastic Surgery, 8th edition (2019) — Scar revision and Z-plasty
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.