The Facts

Phlebitis means inflammation of a vein.

Superficial phlebitis (also called superficial thrombophlebitis), is a condition where the veins close to the surface of the body (superficial veins) become swollen, tender, and red and develop blood clots. When deeper veins (e.g., in a muscle) develop blood clots, it's called deep vein thrombosis (DVT).


Phlebitis occurs in people who develop blood clots in their veins, or when the veins are damaged from intravenous medications or an intravenous catheter. There are two kinds of veins that can be affected: superficial veins and deep veins.

Superficial veins are found in the fatty layer right under the skin and are visible as thin blue lines on the skin surface. The deep veins are not visible and are found in the muscles. The deep veins in the legs are squeezed by the surrounding muscles, which help to move blood from the legs upward to the heart. Since superficial veins aren't surrounded by muscles, there is no squeezing effect and the blood moves more slowly. You're more likely to get phlebitis in veins where the blood flows more slowly than normal, such as varicose veins.

Phlebitis is often caused by an injury to a vein. A blood clot, called a thrombus, can form and stick to the side of the vein. Since there are no muscles to squeeze the clot, it stays stuck inside the vein and blocks blood flow. In general, blood clots that form in the superficial veins do not move or break off. On the other hand, blood clots that form in the deep veins can break off and travel to the lungs, where they can cause difficulty breathing.

Phlebitis can also be a complication of connective tissue disorders such as lupus, or of pancreatic, breast, or ovarian cancers. Phlebitis can also result from certain medications (e.g., potassium solutions and many cancer drugs) that irritate the veins.

Symptoms and Complications

The area around the vein is red, warm, swollen, and often painful. Because the blood in the vein tends to clot, the vein feels hard, not soft like a normal vein. The vein may even feel like a "rope" with knots along its length. When the superficial veins in the legs develop phlebitis, swelling of the ankle or foot is common. Long-standing phlebitis of the leg veins can lead to discoloration around the ankles.

Although uncommon, untreated superficial phlebitis can spread to deep veins. More serious complications occur with DVT, where a blood clot can break free from a deep vein and move towards the lungs. The moving blood clot, called an embolus, can block blood flow to the lungs and is known as a pulmonary embolus.

Making the Diagnosis

The doctor can tell that someone has phlebitis by examining the veins. An ultrasound scan or a Doppler test may be performed to see if there is a blood clot in the deep veins.

Treatment and Prevention

Superficial phlebitis usually improves on its own in a few days, although it may take a few weeks for the lumps and pain to disappear. Treatment usually consists of warm soaks, rest, leg elevation, and a nonsteroidal anti-inflammatory drug (NSAID) such as acetylsalicylic acid* or ibuprofen. If there is evidence of an infection, a short course of antibiotics may also be prescribed.

For superficial phlebitis and DVT, your doctor may suggest that you wear elastic compression stockings. If you have blood clots in the superficial veins (e.g., veins of the leg), the doctor may suggest removing the vein. Rarely, the doctor may remove the blood clot from a superficial vein under local anesthesia.

For DVT, medications such as heparin or warfarin may be used to prevent blood clots from getting bigger.

Doctors might also suggest placing a filter (an umbrella-like device) in a vein to prevent clots that break off from reaching the lungs. Rarely, surgery may also be recommended to bypass or open a vein.

To prevent phlebitis, avoid smoking and participate in moderate physical activity to maintain muscle tone and promote circulation. When travelling for long periods of time, walk around every hour or so and move your legs frequently. Compression stockings may also be helpful. For some people (especially those who have had a blood clot in the past), your doctor may recommend a medication to reduce your chances of developing a blood clot.


*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.