Deep vein thrombosis calf

Overview

Deep vein thrombosis (DVT) is when a blood clot forms in a deep vein, most often in your leg. In the calf, this means the clot is in a deep vein of your lower leg. This can be serious because the clot may break loose and travel to your lungs, which is a medical emergency.

Yes, DVT is relatively common. In the UK, about 1 in 1,000 people develop it each year.

DVT can affect anyone, but it is more common in people over 60, those who have had surgery or an injury, people who are immobile for long periods, and those with certain medical conditions or a family history of blood clots.

Symptoms

Common symptoms

• Pain, swelling, or tenderness in one calf
• The calf may feel warm to the touch
• The skin on the calf may look red or blueish
• A dull ache or cramping sensation

Symptoms in children

• Children with DVT may have similar symptoms to adults: leg pain, swelling, and warmth. But children are less likely to develop DVT, and symptoms can be mistaken for growing pains. If a child has a swollen, painful leg, especially after a long period of inactivity or a recent illness, seek medical advice.

Symptoms in older adults

• Older adults may not have typical symptoms. They might notice only mild swelling or a feeling of heaviness in the leg. Sometimes the first sign of DVT in an older person is shortness of breath or chest pain from a pulmonary embolism, so it's important to check any new leg symptoms.

Causes

Main causes

• Blood clots form when blood flow slows down or stops in a deep vein. This can happen after a long period of sitting or lying still, such as during a long flight or after surgery.
• Injury to a vein, from trauma or medical procedures, can also trigger a clot.
• Certain medical conditions, like cancer or blood clotting disorders, make blood more likely to clot.

Risk factors

• Being over 60
• Having surgery, especially on the legs or hips
• A broken leg or severe muscle injury
• Prolonged bed rest or sitting for long periods (e.g., long-haul flights)
• Obesity
• Pregnancy and the six weeks after giving birth
• Using hormone replacement therapy or birth control pills
• Having cancer or treatment for cancer
• A personal or family history of blood clots

When to see a doctor

See a doctor urgently if:

• If you have sudden swelling, pain, warmth, or redness in one calf, especially if it started after a long period of immobility or after surgery.
• If you have any of the emergency symptoms listed above (chest pain, trouble breathing, coughing up blood).

Book a routine appointment if:

• If you are at higher risk of DVT (for example, due to a family history or a condition like cancer) and you want to talk about prevention, make a routine appointment with your GP.
• If you have had DVT before and are concerned about recurrence, see your doctor for a check-up.

Diagnosis

Your doctor will ask about your symptoms and medical history, and examine your leg. They will usually arrange one or more tests to confirm or rule out DVT.

Tests that may be done

• Ultrasound (compression ultrasound) – this is the most common test. A gel is applied to your leg and a small handheld device is moved over the area to check blood flow and look for clots.
• D-dimer blood test – measures a substance in the blood that can be high when a clot is breaking down. However, high levels can also happen for other reasons, so this test is not enough on its own.
• Venography (less common) – a special dye is injected into a vein and X-rays are taken to see the blood flow.

What to expect at your appointment

The tests are usually done in a hospital outpatient department. An ultrasound is painless and takes about 30 to 60 minutes. If the test shows a clot, treatment will start quickly to prevent the clot from growing or moving. You may be told to wear compression stockings and take blood-thinning medication.

Treatment

Treatment aims to stop the clot from getting bigger, prevent it from breaking off and travelling to your lungs, and reduce the risk of another clot. The main treatment is with blood-thinning medicines (anticoagulants). You will need to take these for at least 3 to 6 months, sometimes longer.

Self-care at home

• Wear compression stockings as prescribed. These help reduce swelling and improve blood flow.
• Elevate your leg when sitting or lying down to help reduce swelling.
• Walk regularly as advised by your doctor, but avoid standing or sitting for long periods.
• Stay hydrated – drink plenty of fluids, especially when travelling.
• Do not massage or rub your calf, as this could dislodge the clot.

Medical treatments

The standard treatment is with medicines that thin the blood, usually injections followed by tablets. These medicines are taken for several months. Your doctor will monitor you with blood tests to make sure the dose is right. In some cases, if you cannot take blood thinners, a filter may be placed in a large vein (the vena cava) to catch clots before they reach the lungs. Never take any blood-thinning medicines without a prescription.

When is surgery considered?

Surgery is rarely needed. In very severe cases, a procedure called thrombectomy may be done to remove the clot directly, or thrombolysis (clot-busting medicines) may be used. This is only considered if the clot is very large and causing serious symptoms, or if blood thinners cannot be used.

Living with this condition

After a DVT in the calf, you will likely need to take blood-thinning medication for several months and wear compression stockings. You can still do most normal activities, but you should avoid prolonged sitting or standing. Your doctor will tell you when it’s safe to return to exercise, work, and travel. It may take weeks to months for swelling and discomfort to fully improve.

Lifestyle tips

• Keep moving – regular walking is good, but avoid high-impact or contact sports until cleared by your doctor.
• If you sit for long periods (e.g., at a desk), get up and move every 30 to 60 minutes.
• On long journeys (car, plane, train), get up and walk regularly, and do calf exercises while seated.
• Stay hydrated and avoid alcohol when travelling.
• Wear your compression stockings as directed, especially during long periods of sitting or standing.

Diet and exercise

You can eat a normal balanced diet. If you are taking blood thinners, you do not need to avoid vitamin K-rich foods (like leafy greens), but try to keep your intake consistent from day to day. Talk to your doctor about any dietary changes. Gentle exercise like walking, swimming, and cycling is encouraged once the initial clot is stable. Avoid heavy lifting or activities that might injure your leg until your doctor says it’s safe.

Mental health and emotional wellbeing

Having a DVT can be scary, and worrying about another clot or a pulmonary embolism is normal. You may feel anxious or down while adjusting to treatment and lifestyle changes. It is important to talk to your doctor or a counsellor if these feelings persist. Support groups can also be helpful.

Prevention

Yes, in many cases. If you are at increased risk, especially after surgery or during long travel, steps can be taken to prevent DVT. These include staying active, getting up and walking regularly, doing leg exercises while seated, staying hydrated, and wearing compression stockings. After surgery, your medical team may give you blood-thinning injections to prevent clots. Always follow your doctor’s advice.

Screening programmes

There is no routine screening for DVT in the general population. However, if you have a strong family history of blood clots or a known clotting disorder, your doctor may recommend periodic check-ups or preventive measures in high-risk situations (such as pregnancy or surgery).

Complications

If left untreated

• Pulmonary embolism (PE) – the most serious complication. A piece of the clot can break off and travel to the lungs, blocking blood flow. This can cause sudden chest pain, trouble breathing, and can be fatal.
• Post-thrombotic syndrome (PTS) – long-term swelling, pain, and skin changes in the affected leg, which can develop months or years after the clot. This can be prevented by wearing compression stockings and treating the DVT promptly.
• Recurrent DVT – if the clot is not fully treated or risk factors remain, you may develop another clot in the same or opposite leg.

Long-term outlook

With prompt treatment, most people with a DVT in the calf recover fully without long-term problems. The risk of a pulmonary embolism is greatly reduced. Some people may have lingering swelling or discomfort, but compression stockings and lifestyle changes can help. Following your treatment plan and attending follow-up appointments is key to a good outcome. Most people can return to their normal activities within a few months.

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