Swollen Legs 🦵
Guide to assessing swollen legs on call: unilateral vs bilateral approach, key differentials (DVT, cellulitis, heart failure, venous disease), red flags, initial investigations, and when to escalate.
🧠 Approach
- Three questions frame everything: unilateral or bilateral? Acute or chronic? Painful, red, or warm?
- Unilateral → exclude DVT and local causes first.
- Bilateral pitting oedema → usually systemic (heart failure, renal/hepatic disease, drugs).
- Bilateral “cellulitis” is rare; reconsider venous eczema, lipodermatosclerosis, or DVT.
📞 What to Ask on the Phone
- One leg or both? Sudden or gradual?
- Pain, redness, warmth, fever?
- SOB or chest pain? (PE)
- Recent surgery, immobility, travel, trauma, new meds?
- Prior VTE, anticoagulation status?
- Numbness, pallor, or cold foot? (ischaemia)
🚨 Red Flags: Escalate Urgently
- Suspected PE: pleuritic pain, haemoptysis, tachycardia, hypoxia, syncope.
- Acute limb ischaemia (6 Ps): pain, pallor, pulselessness, paraesthesia, paralysis, perishingly cold.
- Compartment syndrome: pain out of proportion, tense compartment, pain on passive stretch.
- Sepsis or rapidly spreading cellulitis: crepitus, blistering, severe pain; ?necrotising fasciitis.
- New calf swelling post-op or in an immobile patient: treat as DVT until excluded.
🔍 Key Differentials
DVT
- Clues
- Unilateral, calf/thigh, risk factors (immobility, cancer, prior VTE)
- First steps
- Wells score → D-dimer or ultrasound per VTE pathway
Cellulitis
- Clues
- Spreading erythema, warmth, tenderness, fever; portal of entry
- First steps
- Mark borders; antibiotics per HSE pathway
Heart failure
- Clues
- Bilateral pitting, orthopnoea, ↑JVP, basal creps
- First steps
- CXR, BNP; diuretics with senior input
Chronic venous disease
- Clues
- Chronic, varicose veins, haemosiderin staining, venous eczema
- First steps
- Elevation; compression once infection/DVT excluded
Lymphoedema
- Clues
- Non-pitting, chronic, post-surgery/radiotherapy
- First steps
- Skin care, elevation, specialist referral
Ruptured Baker cyst
- Clues
- Sudden calf pain + popliteal fullness; mimics DVT
- First steps
- Duplex ultrasound to differentiate
Drug-related
- Clues
- Bilateral, gradual; amlodipine, NSAIDs, steroids, pioglitazone
- First steps
- Review medication chart
| Diagnosis | Clues | First steps |
|---|---|---|
| DVT | Unilateral, calf/thigh, risk factors (immobility, cancer, prior VTE) | Wells score → D-dimer or ultrasound per VTE pathway |
| Cellulitis | Spreading erythema, warmth, tenderness, fever; portal of entry | Mark borders; antibiotics per HSE pathway |
| Heart failure | Bilateral pitting, orthopnoea, ↑JVP, basal creps | CXR, BNP; diuretics with senior input |
| Chronic venous disease | Chronic, varicose veins, haemosiderin staining, venous eczema | Elevation; compression once infection/DVT excluded |
| Lymphoedema | Non-pitting, chronic, post-surgery/radiotherapy | Skin care, elevation, specialist referral |
| Ruptured Baker cyst | Sudden calf pain + popliteal fullness; mimics DVT | Duplex ultrasound to differentiate |
| Drug-related | Bilateral, gradual; amlodipine, NSAIDs, steroids, pioglitazone | Review medication chart |
🩺 Examination
- Vitals + NEWS: screen for PE/sepsis if unwell.
- Compare both legs: circumference, pitting (level), colour, warmth, tenderness.
- Skin: erythema (mark borders), ulcers, toe webs (tinea), varicose veins.
- Neurovascular: DP/PT pulses, cap refill, sensation, power.
- If bilateral: JVP, basal creps, ascites.
- Homan sign is unreliable. Do not use to rule DVT in or out.
🔬 Investigations
- Unilateral acute + DVT concern: Wells score → D-dimer ± proximal leg ultrasound (HSE NCG-VTE).
- D-dimer before anticoagulation if using it to rule out.
- PE suspected: ECG, CXR, escalate; CTPA per senior.
- Cellulitis: clinical diagnosis; FBC, CRP, lactate if unwell. Swab only if open wound/atypical.
- Bilateral: U&E, LFTs, albumin, BNP, urine dip; CXR if overloaded.
- No routine leg X-ray unless fracture suspected.
💊 Management
- Treat the cause. Don’t give diuretics for a DVT; don’t miss DVT while treating cellulitis.
- DVT: anticoagulate per local VTE protocol (confirmed, or while awaiting imaging if high risk).
- Cellulitis: antibiotics per HSE guideline, elevation, analgesia. No compression during acute infection.
- Overload: sit up, O₂ if hypoxic, IV diuretic with senior input; monitor urine output and U&E.
- Chronic venous/lymphoedema: elevation, skin care, treat tinea; compression once infection excluded.
- Hold contributing drugs (e.g. amlodipine) if safe; discuss with senior.
- Document: unilateral vs bilateral, pitting, erythema, pulses, working diagnosis.
📋 When to Refer
- Acute limb ischaemia, compartment syndrome, ?necrotising fasciitis: emergency vascular/surgical review.
- Non-healing ulcer, osteomyelitis, diabetic foot: urgent vascular/diabetes input.
- Recurrent cellulitis with venous insufficiency or lymphoedema: vascular/dermatology.
- Unclear after workup: registrar review; consider duplex.
Based on
Related NICE guidance
NICENICE NG158 — Venous thromboembolic diseases: diagnosis, management and thrombophilia testing
Full guidance on nice.org.uk. BetterCall is not endorsed by NICE.
Note Template
Ready-to-use clinical note structure
🕒 08 / 10 / 2026 — 16:09 ATRP re: swollen leg(s) Patient: [age] [sex] Admission Dx: [reason for admission] PMHx: [heart failure, CKD, venous insufficiency, lymphoedema, prior VTE, diabetes] 🧾 Hx: • Onset: [sudden / gradual] — [unilateral / bilateral] — site [R/L/both] • Pain, redness, warmth, fever, systemic symptoms • Immobility, recent surgery/travel, trauma, new medications • SOB, chest pain, haemoptysis (PE screen) • Prior DVT/PE, anticoagulation status 🩺 Exam: • Vitals: HR __ BP __ Temp __ SpO₂ __ • Leg comparison: pitting [Y/N — grade/level], erythema [Y/N — marked borders if present] • Pulses, cap refill, sensation, motor function • JVP, basal crepitations, abdominal ascites • Toe webs / ulcers / varicose veins: [findings] 🔬 Investigations: • Wells score / D-dimer / leg USS: [if unilateral acute — results] • Bloods: [FBC, CRP, U&E, BNP, LFTs — as indicated] • CXR: [if overload/PE concern] 📋 Impression: Leg swelling — [DVT / cellulitis / heart failure / venous disease / lymphoedema / other] 📌 Plan: • [Anticoagulation / antibiotics / diuretics / elevation / analgesia — as appropriate] • Referrals: [vascular / medicine / radiology — or none] • Safety-netting: worsening pain, breathlessness, spreading redness, pulselessness 👤 [Your Name], [Role] IMC: _______
Educational reference only. Medical disclaimer