Medically Reviewed by Sabrina Felson, MD on November 04, 2021
7 min read

Thrombophlebitis is when a blood clot forms in one of your veins and slows the blood flow in the vein. It most often affects your legs, but it can also happen in your arms or other veins in your body. Thrombophlebitis can happen right under the skin or deeper in your leg or arm.

"Thrombo" means clot, and "phlebitis” means inflammation in a vein. That’s the swelling and irritation that happen after an injury.

Phlebitis and thrombosis of the lower extremity superficial veins. You might also hear this called superficial phlebitis or superficial thrombophlebitis. It’s a blood clot in the vein just below the surface of your skin. It doesn’t usually get to your lungs, but superficial thrombophlebitis can be painful, and you may need treatment.

Deep vein thrombosis (DVT). It's a blood clot in a vein deep in your body that can occur with or without phebitis. Most happen in your lower leg or thigh, but they may happen in other parts of your body. A clot like this can get loose and travel through your bloodstream. If it gets to an artery in your lungs and blocks blood flow, it’s called a pulmonary embolism, which can damage your lungs and cause death. This is what makes DVTs are more dangerous than superficial vein thrombosis. DVTs require blood thinners.

Migratory thrombophlebitis. Also called Trousseau's syndrome or thrombophlebitis migrans, it's when the clot comes back in a different part of your body. It often goes from one leg to the other. It’s often linked to cancer, especially of the pancreas or lung.

If the blood flow to one of your veins is slowed because of a clot, you might have:

  • Red, swollen, and irritated skin around the affected area
  • Pain or tenderness that gets worse when you put pressure on the affected area
  • A swollen vein that feels like a tough "cord" under your skin
  • Pain when flexing your ankle (keep in mind that thrombophlebitis can happen in other parts of the body, but it usually happens in the legs)
  • A swollen foot or ankle

If you have any of these symptoms, see your doctor right away.

Call 911 if you have leg pain or swelling or any of the following symptoms:

  • One leg seems warmer than the other or is swollen, red, painful, or irritated
  • The affected limb becomes pale or cold, or you start feeling chills and fever
  • Sudden coughing, which may bring up blood
  • Sharp chest pain or chest tightness
  • Pain in your shoulder, arm, back, or jaw
  • Rapid breathing or shortness of breath
  • Pain when you breathe
  • Severe lightheadedness
  • Fast heartbeat

First, a blood clot forms. This can be due to several things. Most often, it’s caused by blood not moving the way it should through the leg veins. This can happen because of:

Long-term bed rest, such as after a major illness or surgery.

Sitting for a long time, as you would in a car, on a plane, or in some other place where you can’t stretch your legs.

Varicose veins. They cause your blood vessels to stretch too much. This allows blood to pool in the vessel instead of flowing straight through in one direction. This can lead to blood clots.

Anyone who has poor circulation in their legs may be more likely to have this condition. This could include women who may get thrombophlebitis during or after pregnancy. People who’ve been kept in the hospital on an IV are at risk, too. Hospital staffers try to lower this risk by changing the spots where IV lines are placed in the body.

Other things that raise your chances of having this condition include:

  • Certain cancers
  • Use of the hormone estrogen for birth control or hormone replacement
  • Being over age 60
  • Obesity
  • Smoking
  • A family or personal history of blood clots
  • Catheters placed in central veins of the arm or leg
  • Anyone who has a hypercoagulable state
  • if you have had trauma
  • Are immoboloized
  • Have had surgery and are immobolized

The doctor will start by asking about your symptoms and taking a look at veins near the surface of your skin. They’ll do a physical exam. They may also do blood and circulation tests or imaging exams like a CT scan or MRI. They might also do tests like:

Duplex ultrasound. This painless imaging test doesn’t have radiation the way an X-ray does. It uses sound waves to create a picture of your legs. The doctor spreads warm gel on your skin and then rubs a wand over the area where they think the clot is. The wand sends sound waves into your body. The echoes go to a computer, which makes pictures of your blood vessels and sometimes the blood clots.

A radiologist will review the images and send a report to your primary care doctor or to the doctor who requested the ultrasound.

D-dimer test. This is a blood test to look for a protein, called D-dimer, that’s made when a blood clot breaks down. Your doctor will order this test if they think you’ve got a dangerous clot, like a deep vein thrombosis (DVT) or pulmonary embolism (PE).

If your D-dimer level is high, it could mean a clot is breaking down. If your results are negative, it means you probably don’t have a clot. But even if the results are positive, that still doesn’t mean you have a clot. Your doctor will need to order imaging studies to visualize the clot.

MR Venography and CT Venography. If the results of your ultrasound aren’t clear, your doctor will use these imaging studies to confirm the presence of a clot. They will inject a dye into your vein and the image will show up on an X-ray. Possible side effects include pain and an allergic reaction to the dye.

MR angiography (MRA). This test takes a detailed picture of your veins using a large MRI machine. Your doctor will inject a special dye into your veins. It’ll allow them to see your blood vessels. They’ll also be able to see anything that looks unusual, like plaque buildup in your arteries.

CT scan. If your doctor is concerned that a deep vein clot has moved to your lung, they might order this test to get a better image.

Most cases of thrombophlebitis that happen in the shallow veins begin to go away by themselves in a week or two. But on rare occasions, these blocked veins can lead to infection. They can even cause tissue damage from the loss of healthy circulation.

If you need treatment, your doctor will probably give you something to relieve swelling and pain. They may recommend that you keep your leg raised or take over-the-counter aspirin or ibuprofen. They might also suggest you apply heat to the affected leg or arm for 15 to 30 minutes, two to three times daily.

Antibiotics. You might get them if poor circulation leads to an infection.

Blood thinners. These medications are usually reserved for thrombosis with a high risk of embolization to the lungs or brain. Deep vein thrombosis requires anticoagulation for this reason. You can give yourself heparin and enoxaparin (Lovenox) at home through shots under your skin. They help keep the clot from getting bigger. You may also have to take an oral drug like warfarin (Coumadin) for several months or longer to keep clots from coming back. Your doctor will give you regular blood tests to make sure the meds are working.

Blood thinners, like direct thrombin inhibitors and factor Xa inhibitors, are also available. But doctors don’t normally recommend them as the main treatment for thrombophlebitis because they cost more and may cause uncontrollable bleeding. They include apixaban (Eliquis), dabigatran (Pradaxa), edoxaban (Savaysa), and rivaroxaban (Xarelto).

Compression stockings. After the clot has resolved and you are on blood thinners, you may be advised to wear a compression stocking on the leg that was affected. This reduces the risk of post-thrombotic or post-phlebitic syndrome.
They decrease swelling of the leg which decreases pressure in the veins and reduces risk of varicose veins..

Filter. This has much more limited use than suggested here. An IVC filter is used on people who can not safely take anticoagulation and are at risk for DVTs which put the person at risk for pulmonary embolism. The vena cava is the main vein in your abdomen. The IVC filter prevents clots in your legs from breaking loose and traveling to your lungs. You’ll need surgery for this treatment. They are ideally removed within  3 months after placement.

Varicose vein stripping. This can help with veins that cause pain or recurring thrombophlebitis. The doctor makes small cuts to remove a long vein. It doesn’t affect circulation. Veins deeper down can handle more blood.

They’re rare, but you could have:

Pulmonary embolism. If the clot breaks loose, it could move to your lungs and block an artery. This condition can be life-threatening.

Postphlebitic syndrome. It can show up months or years after DVT. It often causes pain, swelling, and a feeling of heaviness in the affected leg or arm. You might hear it called post-thrombotic syndrome, venous stasis syndrome, or chronic venous insufficiency.

Sitting on long drives or flights is a major cause of blood clots. To prevent them:

  • Walk around. Get up for a stroll every hour.
  • Keep moving. Don’t just sit there. Flex your ankles. Or press your feet against the floor or footrest about 10 times an hour.
  • Keep it loose. Don’t wear tight clothing.
  • Stay hydrated. Drink plenty of fluids, but avoid alcohol.
  • Blood thinners. If you have had a clot previously or are at high risk for one, blood thinners may be prescribed prophylactically.