--- title: "Deep vein thrombosis: Symptoms & Treatment | HealthAnswers" description: "Deep vein thrombosis (DVT) — leg blood clot symptoms, pulmonary embolism warning signs, diagnosis, and NHS anticoagulant treatment." url: https://healthanswers.co.uk/conditions/deep-vein-thrombosis/ robots: noindex --- # Deep vein thrombosis: Symptoms & Treatment | HealthAnswers Health A–Z Deep vein thrombosis (DVT) — leg blood clot symptoms, pulmonary embolism warning signs, diagnosis, and NHS anticoagulant treatment. Written by HealthAnswers editorial team Medically reviewed by [HealthAnswers UK doctor review panel](https://healthanswers.co.uk/our-doctors/) Reviewed 3 July 2026 ## Quick answer What is deep vein thrombosis? Deep vein thrombosis is a blood clot in a deep leg vein — causing calf or thigh pain, swelling, warmth, and redness, often one leg only. Part of the clot can break off causing pulmonary embolism (PE) — chest pain and breathlessness — a medical emergency. Risk increases after surgery, immobility, pregnancy, and the combined pill. Treated with anticoagulants (DOACs or heparin/warfarin). Phone 999 if sudden breathlessness or chest pain with leg symptoms. ## Who is this page for? This page is for people in the UK who want a plain-English overview of Deep vein thrombosis, including when to seek help and what NHS care usually involves. It explains general information, not what is wrong with you personally. ## Who should skip this page? Skip this page if you need a diagnosis, a prescription, or emergency care. It cannot replace a GP, pharmacist, NHS 111 or 999. If you are in immediate danger, call 999; for urgent advice that is not life-threatening, call 111 in England, Scotland or Wales, or use your GP out-of-hours service in Northern Ireland. On this page 9 sections ## Key facts about deep vein thrombosis - DVT affects about 1 in 1,000 people yearly in UK — many related to hospital admission or immobility. - Classic signs — unilateral swollen painful calf or leg — but DVT can be silent. - Pulmonary embolism — clot in lung arteries — sudden breathlessness, pleuritic chest pain, collapse. - Diagnosis — Wells score, D-dimer blood test, ultrasound scan of leg veins. - Direct oral anticoagulants (apixaban, rivaroxaban) are standard outpatient treatment for many DVTs. ## Deep vein thrombosis (DVT) — leg clots and PE risk **Deep vein thrombosis** is a **blood clot (thrombus)** in a **deep vein** — usually **leg (iliac, femoral, popliteal)** — sometimes **arm** (PICC lines). **Pulmonary embolism (PE)** — clot **embolises to lungs** — **potentially fatal** — **15%** of untreated symptomatic DVTs may PE. Annual UK incidence **~1 per 1,000** — **hospital-associated** common. ## Symptoms of DVT **Classic unilateral leg:** - swelling — calf or whole leg - pain — especially calf — Homan’s sign unreliable - warmth , erythema - distended superficial veins **May be subtle** — **clinically silent DVT** — high suspicion with risk factors. **Bilateral leg swelling** — think **heart failure**, ** lymphoedema** — less typical isolated DVT. ## Pulmonary embolism — emergency **Symptoms:** - sudden breathlessness - pleuritic chest pain — worse breathing in - tachycardia - haemoptysis - syncope , hypotension — massive PE **Phone 999** — do not wait for GP. ## Risk factors — Virchow triad - stasis — immobility, surgery, long travel, paralysis - endothelial injury — trauma, catheters - hypercoagulability — cancer, thrombophilia, OCP/HRT , pregnancy , COVID-19 **Previous DVT** — strongest recurrent risk. ## Diagnosis **Wells score** — clinical probability **D-dimer:** - negative with low Wells — excludes DVT - positive — non-specific — needs scan **Compression ultrasound** — **gold standard** leg DVT **PE suspected:** - CTPA chest - V/Q scan if contrast contraindicated ## Treatment ### Anticoagulation **DOACs** (direct oral anticoagulants) — **first-line outpatient** for many: - apixaban - rivaroxaban - edoxaban **LMWH → warfarin** — still used — **INR monitoring** **Minimum 3 months** — **provoked DVT** (clear temporary trigger) **Unprovoked** — **extend** — **lifelong** if high bleed risk acceptable — specialist ### Severe PE - ** thrombolysis** — massive PE with haemodynamic compromise - IV heparin **Compression stockings** — **not routine** all DVT now — **PTS prevention** selected cases. ## Prevention **Hospital patients** — **LMWH**, **TED stockings**, **early mobilisation** **High-risk travel:** - move legs , hydrate - avoid excess alcohol - compression stockings if prior DVT **OCP** — **lowest oestrogen** pill if thrombosis risk factors — see [contraceptive pill](https://healthanswers.co.uk/treatments/contraceptive-pill/) — risk discussion. ## Cancer-associated thrombosis **Unprovoked DVT** — **age-appropriate cancer screen** — occult malignancy association. **Treat minimum 6 months** — often **indefinite** if active cancer. ## Do not - massage suspected DVT leg — PE risk - ignore mild calf pain after immobilisation **One swollen leg + breathlessness** — **999 first** — **anticoagulation saves lives** when started promptly. ## ! When to see a GP about deep vein thrombosis Same-day GP or walk-in if one leg swollen, painful, and warm compared to the other — especially after long travel, surgery, or immobility. Phone 999 immediately for sudden breathlessness, chest pain worse on breathing in, coughing blood, or collapse — possible pulmonary embolism. Do not massage a suspected DVT leg. ## Common questions about deep vein thrombosis What are the symptoms of a blood clot in the leg? Pain, swelling, warmth, and redness in calf or thigh — usually one leg. Veins may look more prominent. Some DVTs cause minimal symptoms — high index of suspicion with risk factors. Calf pain like cramp that does not resolve — get checked. What is pulmonary embolism? Blood clot travels to lungs — sudden breathlessness, sharp chest pain worse on deep breath, rapid heart rate, cough sometimes blood-streaked, feeling faint. Large PE causes collapse and death — emergency treatment with anticoagulants and sometimes clot-busting drugs. How is DVT diagnosed? GP calculates Wells score for probability. D-dimer blood test — if low with low Wells score, DVT unlikely. Ultrasound compression scan of leg veins confirms DVT — first-line imaging. CT pulmonary angiography if PE suspected. How long do you take blood thinners for DVT? Minimum 3 months for provoked DVT (clear trigger like surgery). Unprovoked or recurrent clots — often 6 months or lifelong anticoagulation after specialist review. DOACs (apixaban, rivaroxaban, edoxaban) most common — daily tablets without routine monitoring. Can flying cause DVT? Long-haul immobility increases risk modestly — stay hydrated, walk aisle, calf exercises, compression stockings if high risk. Combined oral contraceptive and recent surgery increase risk further — medical advice before travel. What increases DVT risk? Surgery, hospital admission, cancer, pregnancy and postpartum, combined contraceptive pill and HRT, obesity, immobility, previous DVT, thrombophilia, inflammatory conditions, long travel. COVID-19 infection also associated with increased clotting risk. ## Sources - [NHS — Deep vein thrombosis](https://www.nhs.uk/conditions/deep-vein-thrombosis-dvt/) - [NICE — Venous thromboembolic diseases](https://www.nice.org.uk/guidance/ng158)