Deep Vein Thrombosis (DVT)
A blood clot in a deep vein, usually in the leg, which can break off and travel to the lungs.
Quick Summary
Pain, swelling, warmth and redness in one leg, usually the calf. Sometimes no symptoms.
Blood-thinning medicines (anticoagulants) for at least three months.
Long periods of immobility, surgery, pregnancy, cancer, birth control pills, obesity and previous clots.
Overview
DVT happens when blood flows slowly or clots more easily, often during long journeys, after surgery or during illness.
The main danger is pulmonary embolism, when part of the clot travels to the lungs. Sudden breathlessness or chest pain needs emergency care.
Symptoms
Leg swelling
Usually in one leg.
Pain or tenderness
Often in the calf, worse when standing or walking.
Warm, red skin
Over the affected area.
Signs of pulmonary embolism
Sudden breathlessness, chest pain or coughing blood: call 112.
Causes & Risk Factors
Biological Causes
A clot forms when blood flow slows, the vein wall is damaged, or blood clots more easily than usual.
Key Risk Factors
- Immobility Long flights or bus journeys, bed rest, or after surgery.
- Hormones Pregnancy, combined birth control pills and hormone therapy.
- Medical conditions Cancer, heart failure and inherited clotting problems.
Management & Treatment
01. Anticoagulants
Medicines such as apixaban, rivaroxaban or warfarin stop the clot growing.
02. Compression stockings
May help symptoms in some people.
03. Prevention
Moving regularly, staying hydrated, and preventive medicines in hospital.
Frequently Asked Questions
How is DVT diagnosed?
How can I prevent DVT on long journeys?
Can it come back?
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Deep Vein Thrombosis(opens in a new tab) · MedlinePlus, US National Library of Medicine
- DVT (deep vein thrombosis)(opens in a new tab) · NHS