Thrombophlebitis

Thrombophlebitis (throm-boe-fluh-BY-tis) is an inflammatory process that causes a blood clot to form and block one or more veins, usually in your legs. The affected vein might be near the surface of your skin (superficial thrombophlebitis) or deep within a muscle (deep vein thrombosis, or DVT). Causes include trauma, surgery or prolonged inactivity.

DVT increases your risk of serious health problems. It's usually treated with blood-thinning medications. Superficial thrombophlebitis is sometimes treated with blood-thinning medications, too.

Symptoms
Superficial thrombophlebitis signs and symptoms include:

Warmth, tenderness and pain in the affected area
Redness and swelling
Deep vein thrombosis signs and symptoms include:

Pain
Swelling
When a vein close to the surface of your skin is affected, you might see a red, hard cord just under the surface of your skin that's tender to the touch. When a deep vein in the leg is affected, your leg may become swollen, tender and painful.

When to see a doctor
See your doctor right away if you have a red, swollen or tender vein — especially if you have one or more risk factors for thrombophlebitis.

If you have leg swelling and pain and develop shortness of breath or chest pain that worsens when you breathe, go to an emergency room. These might indicate that you have a dislodged blood clot traveling through your veins to your lungs (pulmonary embolism).

Causes
The cause of thrombophlebitis is a blood clot, which can form in your blood as a result of:

An injury to a vein
An inherited blood-clotting disorder
Being immobile for long periods, such as during an injury or a hospital stay
Risk factors
Your risk of thrombophlebitis increases if you:

Are inactive for a prolonged period, either because you're confined to bed or are traveling in a car or plane for a long period
Have varicose veins, which are a common cause of superficial thrombophlebitis
Have a pacemaker or have a thin, flexible tube (catheter) in a central vein, for treatment of a medical condition, which may irritate the blood vessel wall and decrease blood flow
Are pregnant or have just given birth
Use birth control pills or hormone replacement therapy, which can make your blood more likely to clot
Have a family history of a blood-clotting disorder or a tendency to form blood clots
Have had previous episodes of thrombophlebitis
Have had a stroke
Are older than 60
Are overweight or obese
Have cancer
Smoke
If you have one or more risk factors, discuss prevention strategies with your doctor before taking long flights or road trips or if you're planning to have elective surgery, recovery from which will require you not to move much.

Complications
Complications from superficial thrombophlebitis are rare. However, if you develop DVT, the risk of serious complications increases. Complications might include:

Pulmonary embolism. If part of a deep vein clot becomes dislodged, it can travel to your lungs, where it can block an artery (embolism) and become potentially life-threatening.
Post-phlebetic syndrome. This condition, also known as post-thrombotic syndrome, can develop months or even years after you've had DVT. Post-phlebetic syndrome can cause lasting and possibly disabling pain, swelling and a feeling of heaviness in the affected leg.
Prevention
Sitting during a long flight or car ride can cause your ankles and calves to swell and increases your risk of thrombophlebitis. To help prevent a blood clot:

Take a walk. If you're flying or riding a train or bus, walk up and down the aisle once an hour or so. If you're driving, stop every hour or so and move around.
Move your legs regularly. Flex your ankles, or carefully press your feet against the floor or footrest in front of you at least 10 times each hour.
Wear loose clothing.
Drink plenty of nonalcoholic fluids to avoid dehydration.