The Facts

Thrombophlebitis is an inflammation of a vein due to a blood clot. The term comes from a combination of thrombus, meaning blood clot, and phlebitis, meaning inflammation or infection of a vein. When blood clots form, they release a number of toxic chemicals that cause inflammation of the vein.

Thrombophlebitis is classified as either superficial or deep. Deep thrombophlebitis is often called deep vein thrombosis (DVT). This condition is less common but more worrisome than superficial thrombophlebitis. Superficial thrombophlebitis is commonly seen in varicose veins and after insertion of intravenous (IV) tubes in the veins of the arms. Most cases of superficial thrombophlebitis resolve without any medical treatment.


A variety of things can cause inflammation of a superficial vein. One common cause is due to trauma or injury, for example, from IV catheters or some solutions and medications used in hospitals that pierce the vein wall and cause irritation. Any trauma to a vein (like a blow or injury from a car accident) will trigger a local inflammatory reaction that leads to pain, discomfort, redness, and swelling. During this process, there's an increased flow of blood to the injured area, and a blood clot often forms in the inflamed or injured area of the vein.

Formation of blood clots in the deep veins such as the legs or pelvis are often caused by inactivity following surgery, long distance air travel, stroke, or a major accident that causes people to be bedridden for long periods of time. Blood flow in the veins depends on contraction of surrounding muscles, so with extended bed rest, the blood starts to pool and blood clots can easily form.

Sometimes, thrombophlebitis is caused by a bacterial infection in the vein. The usual culprit is a bacteria called Staphylococcus, commonly found on the skin. Thrombophlebitis can also develop in the leg veins of pregnant women, in people with varicose veins, and in some people with cancer of the pancreas. People receiving cancer treatment can also be at risk for developing a DVT. Women over the age of 35 years who smoke and take oral contraceptives are at a higher risk of thrombophlebitis. People who have a pacemaker, a central line (a catheter that is place in a central vein), or are overweight may also be at risk. In certain cases, thrombophlebitis develops without any obvious reason.

Symptoms and Complications

Inflammation in superficial or surface veins, such as those used to insert IV lines in the arm or to draw blood, can produce pain, redness, swelling, warmth, and discomfort. Blood clots that form in superficial veins rarely break loose and travel in the blood to cause blockage (in places such as the lungs).

While many people with DVT have no signs or symptoms, the classic symptoms are:

  • firm swelling of the calf or leg
  • pain or tenderness
  • redness
  • increased local temperature (warmth)
  • dull, aching tightness in the calf, especially with walking
  • dilatation (widening) of the surface veins of the leg
  • shortness of breath (may be the first sign in some people)

DVT is often less painful than superficial thrombophlebitis but can lead to serious complications. The reason is that a blood clot that forms in deeper, larger veins (such as in the legs) can break free and become a traveling blood clot called an embolus. The embolus can travel and lodge in the lung; this condition is called a pulmonary embolism. This is a serious complication of DVT and occurs when the veins of the legs, arms, neck, abdomen, and pelvis are affected.

Because a deep vein clot may not cause symptoms early on, the first sign may be that the clot has broken loose and travelled to the lung. Symptoms of a pulmonary or lung embolus are breathlessness, fast heart rate (palpitations), rapid breathing (panting), chest pain, and coughing up blood. If you have any of these symptoms, you need to get emergency medical care right away.

Making the Diagnosis

To diagnose superficial thrombophlebitis, doctors will take a medical history (asking about symptoms) and do a physical examination. As well, an ultrasound of the suspected veins may be done.

For DVT, doctors look for signs of swelling and enlargement of the calf (due to swollen leg veins). A diagnosis of DVT is usually confirmed with a Doppler test. This is an ultrasound test that detects differences in echoes or sounds made by blood flow in the obstructed veins. Doppler ultrasound can easily detect the presence of blood clots in deep veins. Blood tests may also be performed to check for certain substances that are increased when a blood clot is present.

Treatment and Prevention

To relieve mild inflammation and discomfort in superficial thrombophlebitis, your doctor may suggest elevating the affected area and applying warm moist packs to it for 15 to 20 minutes at a time throughout the day. Pain medications or anti-inflammatory medications may also be prescribed. People with superficial thrombophlebitis should try to stay active (walk around). If the inflammation and symptoms lasts longer than a day or two, or if symptoms become worse, see a doctor as soon as possible. Compression stockings are highly recommended for people with thrombophlebitis of the leg veins.

In cases where the thrombophlebitis is due to an infection, treatment with antibiotics often takes care of the problem. In rare cases, when the antibiotics aren't enough to control the infection, surgical removal of the inflamed portion of the vein may be required.

Once a DVT has been diagnosed, doctors may prescribe blood-thinning (anticoagulant) medications such as heparin, low-molecular weight heparin, or warfarin.* These anticoagulant medications make the blood less likely to clot and help prevent new blood clots from forming.

Blood thinning treatment is started in the hospital so you can be closely looked after; although the hospital stay is relatively short, around 3 to 4 days. Your family doctor can adjust the dose of medications without you going back to the hospital. When there aren't any complications, people with DVT can usually return to normal activity within 1 or 2 months. Blood thinning medications have to be taken anywhere from 3 to 6 months, depending on the cause of your blood clots.

For some people, taking long-term warfarin therapy may be necessary to prevent new blood clots from forming. When medications cannot be used, a radiological procedure may be needed to either place a filter (an umbrella-like device) into a vein in the abdomen to prevent clots from travelling to the lungs or to remove or bypass the blood clot.

In some women, the use of certain types of oral contraceptives may increase the risk for forming blood clots. The risk is higher for women over 35 years of age who smoke or have a history of previous blood clots. If you take birth control pills and smoke, you should stop smoking to lower your risk for thrombophlebitis or DVT.

To help prevent clots, avoid long periods of immobility during long car trips or airplane flights. Try to walk around and stretch for a few minutes every hour or so. Elevate your legs above your heart level if possible, and if you have a history of blood clots, wear support stockings or socks (also called compression stockings), and drink plenty of fluids. Some people may be prescribed a low-molecular weight heparin to prevent blood clots during a long journey (e.g., airplane trip).


*All medications have both common (generic) and brand names. The brand name is what a specific manufacturer calls the product (e.g., Tylenol®). The common name is the medical name for the medication (e.g., acetaminophen). A medication may have many brand names, but only one common name. This article lists medications by their common names. For information on a given medication, check our Drug Information database. For more information on brand names, speak with your doctor or pharmacist.