DVT (deep vein thrombosis) is a blood clot in a vein, usually the leg. DVT can be dangerous. Get medical help as soon as possible if you think you have DVT.
Urgent advice: Ask for an urgent GP appointment or call 111 if:
You think you have DVT.
Symptoms of DVT in the leg are:
- throbbing or cramping pain in 1 leg (rarely both legs), usually in the calf or thigh
- swelling in 1 leg (rarely both legs)
- warm skin around the painful area
- red or darkened skin around the painful area
- swollen veins that are hard or sore when you touch them
These symptoms also happen in your arm or tummy if that's where the blood clot is.
What DVT in a leg can look like
Immediate action required: Call 999 or go to A&E if:
You have symptoms of DVT, such as pain and swelling and:
- chest pain
DVT can be very serious because blood clots in your veins can break loose, travel through your bloodstream and get stuck in your lungs. This is called a pulmonary embolism.
A pulmonary embolism can be life threatening and needs treatment straight away.
Who is more likely to get DVT
A DVT is more likely to happen if you:
- are over 60
- are overweight
- have had DVT before
- take the contraceptive pill or HRT
- have cancer or heart failure
- have varicose veins
There are also some temporary situations when you're at more risk of DVT. These include if you:
- are staying in or recently left hospital – especially if you cannot move around much (like after an operation)
- are confined to bed
- go on a long journey (more than 3 hours) by plane, car or train
- are pregnant or if you've had a baby in the previous 6 weeks
- are dehydrated
Sometimes DVT can happen for no obvious reason.
How DVT is diagnosed
If a doctor thinks you have DVT, you should be referred to hospital within 24 hours for an ultrasound scan. The scan shows whether blood is flowing normally through the vein.
You may also have an X-ray of the vein (venogram). For this, you will be injected with a dye to show where the blood clot is.
Treatment of DVT
You may have an injection of an anticoagulant (blood thinning) medicine called heparin while you're waiting for an ultrasound scan to tell if you have a DVT.
If anticoagulant medicines are not suitable, you may have a filter put into a large vein – the vena cava – in your tummy. The filter traps and stops a blood clot travelling to your heart and lungs.
A newer treatment involves breaking up and sucking out the clot through a small tube in the vein. You usually need to take anticoagulant medicine for several months after this treatment.
DVT in pregnancy is treated differently. It is treated with anticoagulant injections for the rest of the pregnancy and until the baby is 6 weeks old. Read more about DVT in pregnancy.
Recovery from DVT
Some lifestyle measures will help you recover from DVT.
After you leave hospital, you will be encouraged to:
- walk regularly
- keep your affected leg raised when you're sitting
- delay any flights or long journeys until at least 2 weeks after you start anticoagulant medicine
Tips to prevent DVT
- stay a healthy weight
- stay active – taking regular walks can help
- drink plenty of fluids to avoid dehydration – DVT is more likely if you're dehydrated
- do not sit still for long periods of time – get up and move around every hour or so
- do not cross your legs while you're sitting, it can restrict blood flow
- do not smoke – get support to stop smoking
- do not drink lots of alcohol
Going on a long journey
If you're travelling for 3 hours or more by plane, train or car, there are things you can do during the journey to reduce your risk of DVT. These include drinking plenty of water and avoiding alcohol.
Going into hospital
If you go into hospital, your healthcare team should check your risks of DVT.
If they think you're more likely to get DVT, you may be given treatment to prevent it, such as medicine or compression stockings (knee-high elastic socks that help your blood circulation), while you're in hospital.
You may continue treatment after you leave hospital because a blood clot can happen weeks later.
You can also help protect yourself against DVT while you're in hospital by:
- staying active and walking around if you can
- moving your toes (up and down) and ankles (in circles) if you have to stay in bed – your healthcare team may give you some exercises to do
Page last reviewed: 23 October 2019
Next review due: 23 October 2022