Leg Ulcer
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Direct answer
Site predicts aetiology in lower-limb ulceration: a shallow, granulating ulcer in the gaiter area above the medial malleolus, ringed by pigmented skin and oedema, is venous — seven in ten leg ulcers; punched-out ulcers over the toes, foot or pressure points with absent pulses and rest pain are arterial; a painless deep ulcer beneath a callus at a metatarsal head belongs to the neuropathic, usually diabetic, foot. The single measurement that must precede every compression bandage is the ankle-brachial index — compression against an ischaemic limb is how ulcers become amputations. Ulcers that fail to heal within three months deserve a biopsy, because Marjolin's ulcer — squamous carcinoma arising in a chronic wound — is the malignant end of neglect.
What you must remember
- Venous ulcer profile: gaiter area, shallow with sloping edges and a granulating base, surrounded by haemosiderin staining, lipodermatosclerosis (the inverted champagne-bottle leg), varicose eczema, ankle flare and pitting oedema — CEAP class C6 in venous-clinic language.
- Compression therapy: four-layer bandaging or graduated stockings delivering roughly 40 mmHg at the ankle, strictly after documenting an ankle-brachial index of 0.8 or more; compression heals most venous ulcers within about 12 weeks, and continued stockings halve recurrence.
- Arterial ulcer profile: punched-out and deep over toes, heel or pressure points, hairless shiny cold skin, absent pulses, claudication and night rest pain relieved by hanging the leg down; duplex first, then angioplasty or bypass — local wound care fails until flow is restored.
- Neuropathic ulcer: beneath a callus over the metatarsal heads or heel, painless, often probing to bone; treatment is offloading (total contact cast) and debridement — dressings alone never heal a pressure-driven ulcer.
- Mixed-disease caution: diabetes calcifies calf vessels and falsely raises the ankle-brachial index, so toe pressures or duplex decide when the index is unreliable.
- The biopsy rule: any ulcer unhealed at three months, enlarging, with everted or rolled edges, or disproportionately painful — punch biopsy for squamous carcinoma (Marjolin's ulcer); Indian addenda are tuberculous ulcers and the sickle-cell ulcers of central India over the medial malleolus in young patients.
- Local care framework: the TIME mnemonic — tissue debridement, infection control, moisture balance, edge advancement — organises wound-bed preparation whatever the aetiology.
Reading an ulcer by its site
Three patients teach the whole topic. A 58-year-old teacher has a 4 cm shallow ulcer above the left medial malleolus of four months' duration, with brown staining and an aching, swollen leg. Venous ulcer: check the index (0.9 — safe), four-layer bandaging weekly, and the ulcer granulates inward week by week; when healed, class 2 stockings for life and a duplex to plan varicose vein surgery.
The second, a 64-year-old smoker, has a black-bordered, punched-out ulcer on the great toe tip with rest pain at night relieved by dangling the foot. Arterial: index 0.5, duplex shows a short superficial femoral occlusion, angioplasty restores flow, and only then does the toe ulcer begin to heal — debriding an ischaemic toe before revascularisation simply enlarges the wound. The third, a 50-year-old diabetic, walks in on a callus over the second metatarsal head under which a probe finds a painless cavity to bone: neuropathic ulcer — total contact cast, offloading footwear for life, and an X-ray or MRI for osteomyelitis. Three ulcers, three mechanisms, three entirely different first prescriptions that happen to share only the word "ulcer".
One rule before every bandage
NBE's most repeated leg-ulcer question is the pre-compression ankle-brachial index, with the threshold (0.8) keyed; the distractor is the eager "apply four-layer bandage" answer that costs an ischaemic limb. The second tier is pattern-matching: gaiter plus pigmentation equals venous, toes plus rest pain equals arterial, painless under callus equals neuropathic. Marjolin's ulcer is the quotable pearl — squamous carcinoma in a long-standing scar or ulcer, biopsied when an old ulcer changes character. And the Indian extension pairs sickle-cell ulcers of central India and tuberculous ulcers with the systematic differentials, earning viva marks for thinking beyond the three common types.
Frequently asked questions
Which is the commonest leg ulcer and where does it occur?
Venous ulcer, about 70% of leg ulcers, in the gaiter area above the medial malleolus with surrounding pigmentation and lipodermatosclerosis.
What ankle-brachial index is required before compression?
0.8 or above; below that, compression risks ischaemic injury and the limb needs vascular assessment first.
What is Marjolin's ulcer?
Squamous cell carcinoma arising in a long-standing chronic ulcer or scar — suspected when an old ulcer enlarges, develops everted edges, or becomes painful, and confirmed by biopsy.
Where do neuropathic ulcers typically occur?
Under callus over plantar pressure points — the metatarsal heads and heel — and they are painless with preserved skin perfusion.
Why do arterial ulcers hurt more at night?
Rest pain from severe ischaemia worsens lying flat as gravity assistance to perfusion is lost, and is relieved by dangling the foot — Buerger's positive test.