Venous leg ulcer assessment and compression

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

A venous leg ulcer is an open lesion below the knee, usually in the gaiter region, caused or sustained by chronic venous hypertension. Superficial reflux, deep reflux, post-thrombotic obstruction, calf-pump failure, restricted ankle movement and obesity may contribute. The appearance is often a shallow irregular exudative wound surrounded by oedema, pigmentation, venous eczema or lipodermatosclerosis, but morphology cannot establish safe treatment. Arterial disease is common in the same age group, and inflammatory, neuropathic, pressure-related and malignant ulcers can imitate a venous wound. Assessment must therefore define the wound, perfusion, infection status, mobility, comorbidity and venous anatomy.

Compression is the central healing treatment after arterial safety checks. ESVS recommends multilayer or inelastic bandages or adjustable garments delivering at least 40 mmHg at the ankle for active venous ulceration, with superimposed stockings up to 40 mmHg as an option for small recent ulcers. Mixed arterial-venous disease is a different prescription: modified pressure below 40 mmHg may be considered only under close clinical supervision when ankle pressure is above 60 mmHg; sustained compression is not recommended below that ankle pressure, toe pressure 30 mmHg or ABPI 0.6. Wound care controls exudate and protects the bed, while duplex and early treatment of superficial reflux address the haemodynamic cause. Antibiotics are reserved for clinical infection, not bacterial colonisation.

Key points

At first assessment document ulcer site, length, width, depth, edge, bed, exudate, pain, surrounding skin and limb oedema; examine pulses and the contralateral limb.
Perform objective arterial assessment before compression with ankle pressure and ABPI, adding toe pressure when ABPI is unreliable; avoid sustained compression below ankle pressure 60 mmHg, toe pressure 30 mmHg or ABPI 0.6.
For an active venous ulcer with adequate perfusion, trained staff should apply multilayer or inelastic bandaging or an adjustable garment targeting at least 40 mmHg at the ankle to improve healing.
Do not use sustained compression when ankle pressure is below 60 mmHg, toe pressure below 30 mmHg or ABPI below 0.6; mixed ulcers may receive less than 40 mmHg only under close supervision when ankle pressure exceeds 60 mmHg.
Most leg ulcers are colonised rather than infected: do not take a routine initial swab and do not prescribe antibiotics unless redness or swelling spreads beyond the ulcer, warmth, increasing pain or fever indicates clinical infection.
Refer a below-knee ulcer unhealed after two weeks and every healed venous ulcer to a vascular service; duplex identifies superficial reflux, and early endovenous ablation with compression accelerates healing when reflux is present.
After closure continue long-term compression when safe and address superficial incompetence, because recurrence is common and healed skin still represents CEAP C5 disease.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Superficial venous reflux

Incompetent saphenous and tributary valves transmit high ambulatory pressure toward gaiter skin; superficial reflux remains treatable even when deep reflux also exists.

Deep venous disease

Post-thrombotic reflux or iliac outflow obstruction maintains venous hypertension and can combine with superficial disease, reduced mobility and poor calf-pump ejection.

Mixed arterial disease

Atherosclerotic inflow limitation can coexist with venous hypertension. It does not erase the venous component, but it narrows safe compression pressure and may require revascularisation.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Sustained venous pressure
Reflux, obstruction and weak calf ejection prevent pressure falling during walking, exposing distal veins and capillaries to chronic ambulatory hypertension.
2
Inflammatory tissue injury
Capillary leakage, leukocyte activation, iron deposition and oedema cause eczema and fibrosis while impairing oxygen and nutrient exchange in the gaiter skin.
3
Failure of skin repair
Fragile inflamed tissue breaks after minor trauma or spontaneous injury; exudate, oedema and persistent pressure keep the wound in a chronic inflammatory state.
4
Compression effect
External pressure reduces venous diameter and oedema, improves valve coaptation and calf-pump efficiency, and thereby shifts the wound environment toward healing.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Typical venous wound

Usually shallow, irregular and exudative around the medial or lateral gaiter region, with oedema, varicosities, pigmentation, eczema, lipodermatosclerosis or atrophie blanche. Pain varies and may increase during dressing change.

Arterial component

A distal punched-out wound, cool shiny skin, reduced pulses, dependent rubor, rest pain or pain on elevation suggests arterial disease; mixed ulcers can retain venous skin changes.

Clinical infection

Spreading redness or swelling beyond the ulcer, local warmth, increased pain and fever support infection. Odour, exudate or a positive swab alone can reflect colonisation and do not prove invasive infection.

Atypical ulcer

Unusual location, undermined violaceous border, retiform purpura, rolled edge, nodular tissue or progressive ulceration despite adequate haemodynamic care suggests inflammatory, vasculitic or malignant disease.

Functional drivers

Reduced ankle range, immobility, obesity, pain and inability to manage compression weaken the calf pump and adherence. These factors are treatment targets rather than reasons to abandon compression.

Red flags requiring action

Rest pain, a cold or pale foot, gangrene, rapidly increasing necrosis, absent pulses or abrupt pain after compression requires urgent arterial assessment and cessation of sustained compression.
Fever, hypotension, rapidly spreading redness, crepitus or severe pain out of proportion suggests sepsis or necrotising fasciitis and requires hospital referral.
Exposed or probeable bone, deep persistent pain, sinus formation or failure despite appropriate care raises concern for osteomyelitis and needs specialist assessment.
An atypical site, rolled or everted edge, excessive granulation, rapid growth or failure to improve despite adequate compression should prompt biopsy or dermatology assessment for malignant or inflammatory ulceration.
Sudden unilateral swelling or chest symptoms in a patient with an ulcer requires urgent VTE assessment rather than attribution to chronic venous disease.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Ankle pressure and ABPIFirst step
Why
Quantify arterial perfusion before compression and detect a mixed arterial-venous ulcer requiring modified or deferred pressure.
Interpretation and limitations
ABPI above 0.8 generally supports full compression in ESVS guidance; 0.6–0.8 requires specialist interpretation and modified compression. Below 0.6 or ankle pressure below 60 mmHg precludes sustained compression.
02
Toe pressure or arterial duplex
Why
Assess perfusion when diabetes, renal disease, neuropathy or a high incompressible ABPI limits the ankle measurement.
Interpretation and limitations
Toe pressure below 30 mmHg is an ESVS boundary against sustained compression. Arterial duplex localises disease and supports revascularisation planning when perfusion is impaired.
03
Full lower-limb venous duplex
Why
Identify superficial and deep reflux or obstruction and plan intervention that can accelerate healing or reduce recurrence.
Interpretation and limitations
Treatable superficial incompetence supports early endovenous ablation alongside compression; deep reflux does not by itself contraindicate superficial treatment, but proximal obstruction may alter sequencing.
04
Structured wound measurement
Why
Record maximal length and width, depth, tissue type, edge, exudate, surrounding skin and pain at a reproducible baseline.
Interpretation and limitations
Serial area reduction supports healing. Stagnation despite correct compression triggers review of pressure delivery, perfusion, infection, adherence, venous anatomy and an atypical diagnosis.
05
Microbiology only after reassessment
Why
Guide narrower antibiotic selection when clinical infection worsens or fails to improve as expected after initial treatment.
Interpretation and limitations
Do not swab routinely at first presentation. If needed later, clean the ulcer first; interpret the result with clinical response because colonising organisms are expected.
06
Biopsy or targeted imaging
Why
Investigate malignancy, vasculitis, osteomyelitis or another atypical cause when morphology, pain or healing trajectory is discordant.
Interpretation and limitations
Biopsy should sample an appropriate edge and bed under specialist direction; suspected bone infection may require imaging and tissue sampling rather than a surface swab.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Arterial ulcer

Distal punched-out wounds, rest pain, cool skin and weak pulses indicate ischaemia; objective pressures determine whether arterial treatment takes priority.

Neuropathic or pressure ulcer

Loss of protective sensation and a pressure-bearing site suggest neuropathic injury, although oedema and venous disease may coexist and complicate healing.

Inflammatory ulcer

A violaceous undermined edge, purpura or extreme pain can indicate pyoderma gangrenosum or vasculitis, for which debridement or compression decisions need specialist input.

Malignant ulceration

An everted or rolled edge, exuberant tissue, bleeding or failure despite correct care warrants biopsy for squamous malignancy or another tumour.

Infective ulcer

Spreading erythema, warmth, increasing pain and fever indicate clinical infection; surface colonisation, odour and exudate alone are insufficient.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01First assessment pathwayOpen lower-leg ulcerFirst stepUse at initial presentation before assuming venous causation, prescribing antibiotics or selecting compression pressure.

1Record duration and recurrence, pain, mobility, VTE and arterial history, diabetes, smoking, medicines and previous treatment; measure and describe the wound and examine both legs.
2Identify serious infection, acute ischaemia, DVT and atypical ulcer features requiring urgent or specialist care.
3Measure ankle pressure and ABPI, add toe pressure or arterial duplex if incompressibility is likely, and arrange full venous duplex to map reflux and obstruction.
4If perfusion is adequate, begin therapeutic compression delivered by trained staff with an appropriate dressing for exudate and wound protection.
5Refer to a vascular service once a below-knee ulcer has not healed within two weeks; do not wait for failure of months of community dressings.

02Compression pathwayPressure chosen from perfusionUse after objective arterial assessment and whenever pain or deterioration occurs under a compression system.

1For a venous ulcer with adequate arterial perfusion, select multilayer or inelastic bandages or an adjustable garment targeting at least 40 mmHg at the ankle.
2For mixed disease, consider modified compression below 40 mmHg only under close clinical supervision and only when ankle pressure exceeds 60 mmHg; incorporate toe pressure and symptoms.
3Avoid sustained compression if ankle pressure is below 60 mmHg, toe pressure below 30 mmHg or ABPI below 0.6, and seek arterial assessment or revascularisation options.
4Check comfort, colour, warmth, capillary refill, sensation, slippage and pressure points soon after application; discontinue and reassess if severe pain or ulcer deterioration follows.
5Remeasure the limb and refit as oedema falls, because pressure and device position change with circumference.

03Infection pathwayColonisation versus infectionUse when exudate, odour, redness, warmth or pain raises a question about antimicrobial treatment.

1Look for redness or swelling spreading beyond the ulcer, local warmth, increasing pain, fever or systemic illness; do not equate colonisation, odour or exudate with infection.
2Do not take an initial routine swab and do not give antibiotics to promote healing in an ulcer without clinical infection.
3For clinical infection, use an oral antibiotic when possible according to NICE choice, severity, allergy, renal or hepatic function and pregnancy; review IV treatment at 48 hours.
4Reassess if worse at any time or not improving within two to three days; then clean and sample the wound if microbiology will guide a change, and refer severe infection to hospital.

04Healing and preventionTreat reflux and prevent recurrenceUse once venous duplex identifies superficial incompetence or when the wound has closed.

1Continue effective compression and refer for early endovenous ablation when active ulceration coexists with superficial reflux; combined treatment accelerates healing.
2After closure, confirm durable skin care, calf-pump activity and a long-term compression plan matched to perfusion and ability to apply the garment.
3Treat incompetent superficial veins in a healed-ulcer limb to reduce recurrence, and provide rapid re-entry to care if skin breakdown returns.

Key medicines and prescribing safety1 treatment · regimens, roles and cautions

Treats a clinically infected leg ulcer with spreading inflammation, warmth, increasing pain or fever; it does not accelerate healing of a colonised uninfected ulcer.

Flucloxacillin for clinically infected ulcer

Take 500 mg to 1 g orally four times daily for 7 days when NICE first-choice treatment is appropriate; 1 g four times daily was off label in the cited guidance.

Check immediate penicillin hypersensitivity, hepatic history, renal or hepatic impairment, pregnancy and interacting medicines. Review if worsening or not improving within two to three days and use microbiology to narrow therapy when needed.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Cellulitis and sepsis

Loss of skin barrier permits invasive infection, which can spread beyond the wound and become systemic, especially with diabetes or immunosuppression.

Contact dermatitis

Repeated dressings, adhesives and topical products can sensitise periwound skin, increasing itch, exudate and apparent inflammation despite microbiologically inactive disease.

Ulcer recurrence

Skin closure does not correct reflux, obstruction or pump failure; recurrence is common without sustained compression and appropriate venous intervention.

Malignant transformation

Rare chronic wounds can develop squamous carcinoma, while primary skin cancers can masquerade as venous ulcers; an atypical trajectory requires biopsy.

Functional decline

Pain, exudate, odour and bulky compression reduce sleep, mobility and social participation, weakening the calf pump and further slowing recovery.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Measure wound dimensions using the same method and photograph according to consent and local practice; compare trajectory rather than relying on subjective appearance.
At every compression change assess foot colour, warmth, sensation, new pain, device slippage and pressure injury, especially in mixed disease or neuropathy.
Review exudate, odour, surrounding erythema, warmth, pain and systemic symptoms; antibiotic response should begin within two to three days even though full resolution takes longer.
Check whether prescribed ankle pressure is actually being delivered and whether the patient can tolerate or self-manage the device; refit as oedema decreases.
Reconsider perfusion, adherence, diagnosis, infection and venous anatomy when healing stalls; an unchanging wound is a signal to reassess causes, not merely switch dressings.
After healing, monitor skin integrity, recurrence and compression use, and ensure the vascular intervention plan for superficial incompetence is complete.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

The ratio needs context

ABPI is one part of perfusion assessment. Absolute ankle pressure and toe pressure protect against errors from low systemic pressure or calcified incompressible ankle vessels.

Compression needs a target

Saying that a wound is bandaged does not establish treatment. Healing evidence concerns trained application of systems that deliver a defined ankle pressure and are reviewed as limb size changes.

Colonisation is expected

Bacteria on a chronic wound do not establish infection. Antibiotics are prompted by tissue invasion signs and systemic response, while routine initial swabbing produces results that can encourage overtreatment.

Early reflux treatment matters

Compression treats venous hypertension while worn; early endovenous ablation treats a major source of reflux and accelerates healing when suitable superficial incompetence is present.

Closure starts prevention

Recurrence is common after healing. Long-term compression, skin surveillance, activity and treatment of reflux are core care for C5 disease rather than optional aftercare.

Pain is diagnostic data

Expected wound pain still deserves treatment, but abrupt severe pain under compression, rest pain or pain out of proportion should trigger perfusion and serious-infection reassessment.

11Common pitfallsFrequent interpretation and management errors.

01
Applying standard high compression before ankle and toe perfusion assessment can convert a mixed ulcer into an ischaemic injury.
02
Using ABPI alone in diabetes may accept a falsely high result from medial calcification; toe pressure or arterial duplex is then required.
03
Swabbing every ulcer on arrival and treating growth with antibiotics confuses colonisation with infection and promotes avoidable antimicrobial exposure.
04
Waiting months for dressings to fail before vascular referral misses the NICE two-week criterion and delays duplex and causal reflux treatment.
05
Changing dressings repeatedly when an ulcer stalls can distract from inadequate pressure, poor adherence, arterial disease, persistent reflux or an atypical diagnosis.
06
Stopping all compression permanently after healing abandons the main recurrence-prevention strategy when perfusion remains adequate.
07
Assuming deep reflux makes superficial ablation futile is incorrect; selected patients still gain healing benefit from treatment of superficial incompetence.

Find your next topic