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Phlebitis of the Leg Veins

Phlebitis is an inflammation of a vein. The vein is hot, red and lumpy. The lump is tubular in shape and it is tender to touch, it may throb and walking may be painful. The cause of phlebitis in the leg is most often a clot in the vein just under the skin. It can disperse and the phlebitis then gets better, but sometimes phlebitis is serious and the condition may become dangerous.


What is Phlebitis?

The vein becomes inflamed either due to a blood clot (thrombus) or because the vein walls are damaged. For this reason, the terms phlebitis and thrombophlebitis are used almost interchangeably. There are two types of phlebitis – superficial phlebitis affects the veins close to the surface of the skin and is usually not too serious; deep vein thrombophlebitis is more serious and affects the larger, deeper veins, frequently in the legs. Deep vein thrombophlebitis can be very serious if a blood clot breaks away and travels to the lungs, which would result in a pulmonary embolism.

What Are The Symptoms of Phlebitis?

In the case of superficial vein phlebitis, symptoms may not appear,and if they do they generally tend to be pain, sensitivity, redness and bulging of the vein. The symptoms of deep vein thrombophlebitis are similar, but pain might be experienced throughout the entire limb, or the whole limb might suddenly swell. Some might also experience a fever.

As you can see in this photograph of phlebitis, the skin over the vein is often discoloured but sometimes there may be nothing to see, particularly if the vein is a little deeper. This patient had quite a lot of tenderness.  An ultrasound scan confirmed that there was clot in the vein and blood thinning medication was prescribed.

Ultrasound of Vein With Phlebitis


Ultrasound of Leg Veins: The normal vein shows as a dark circle. The vein with clot appears with a grey “lump” of clot.

What causes phlebitis?

Phlebitis is caused by blood clots which can form due to venous injury, or as a complication from a surgical procedure. There are also certain risk factors that increase the chances of a blood clot forming:

  • Obesity
  • Smoking
  • Pregnancy
  • Sedentary lifestyle
  • Immobility for long periods
  • Varicose veins
  • Some oral contraceptives and hormone replacement therapy (HRT)
  • Certain medical conditions (cancer, blood disorders)

Can phlebitis be prevented?

Although phlebitis cannot always be prevented, controlling the risk factors can help:

  • Stay active and exercise frequently
  • Take walks on long flights and wear flight socks
  • Stop smoking
  • Lose weight (if overweight)

Is Phlebitis Dangerous?

Phlebitis does not usually result in serious complications. However, if the clot in the superficial vein is extensive and if it involves the area where the superficial vein and a deep vein come together that is near the groin or behind the knee, a DVT can develop.

Sometimes people are unaware that they have a DVT until they experience a life-threatening complication. The most common and serious complication of DVT is a PE. A PE occurs when a piece of the blood clot breaks off and travels to the lungs, where it blocks blood flow.

Symptoms of a PE include:

  • unexplained shortness of breath
  • chest pain
  • coughing up blood
  • pain with deep breathing
  • rapid breathing
  • feeling lightheaded or passing out
  • fast heart rate

What is the treatment for phlebitis?

Measures for superficial phlebitis you can take to treat it include:

  1. Keeping the leg raised
  2. Wear compression stockings
  3. Use anti-inflammatory medication
  4. Use a cold flannel to ease pain
  5. Keep moving to help the flow of blood


A specialist might also prescribe anticoagulants (blood-thinners) to stop additional blood clots forming and clot-dissolving medication for cases of deep vein thrombophlebitis. In some cases, the surgical removal of blood clots might be necessary or a bypass of an injured vein.

Phlebitis versus Cellulitis versus Varicose Eczema of the Leg

These three conditions may be difficult to distinguish just by looking at the leg. In phlebitis, the problem is a clot in the vein, in the case of cellulitis the problem is a bacterial infection. For phlebitis, blood thinning medication may be necessary and antibiotics are not needed. In cases of cellulitis, antibiotics are required. Both phlebitis and cellulitis are urgent and potentially very serious. Both phlebitis and cellulitis can be fatal if not treated properly. 

Varicose eczema is a reaction of the skin to the damage caused by faulty leg veins. Varicose eczema can lead to a leg ulcer but it is not urgent and the ulcer if it does occur develops slowly. Neither antibiotics or blood thinning medication is required for people with varicose eczema.

The only way to accurately diagnose these three conditions is by a duplex ultrasound scan.


Phlebitis is commonly misdiagnosed and more importantly it is very often mistreated.

Essential facts about phlebitis of the Leg Veins:

  1. Phlebitis is not caused by an infection and antibiotics are not necessary. Recent reviews in the medical literature suggest that antibiotics are frequently prescribed for phlebitis. Not only is this ineffective, but it costs our healthcare system and it may contribute to antibiotic resistance. 
  2. Phlebitis most commonly affects the leg veins and it causes swelling, tenderness and redness along the vein. Less common sites include the arm and the chest.
  3. The diagnosis requires a duplex ultrasound scan. Conditions such as cellulitis can mimic phlebitis so confirming the correct diagnosis with a duplex ultrasound scan is essential and it ensures you get the right treatment.
  4. The fundamental problem causing the inflammation in the vein is clot formation which can spread to the deep veins causing a deep vein thrombosis and pulmonary embolism. Many experts suggest that the term phlebitis should be replaced by the term superficial venous thrombosis. This term more accurately describes the potential for DVT.
  5. The duplex ultrasound scan should not only check the area that is painful, but both legs should be examined for a possible deep vein thrombosis. When someone has phlebitis, they can be in a so-called hypercoagulable state in which the blood is sticky. That means that clots can develop elsewhere in the body, including in the deep veins of the other leg as well.
  6. Phlebitis in varicose veins often recurs and people with varicose veins and phlebitis should have treatment to deal with their varicose veins.
  7. Phlebitis in the absence of any varicose veins is a particularly serious condition. Some people with this condition have an unsuspected malignancy and so careful screening is needed to ensure they have cancer treatment as soon as possible. 

Guidelines from both  America and the UK,  indicate that phlebitis in the veins in the legs can give rise to clots that travel to the lungs. These clots are called Pulmonary Emboli (PE’s) and they can be life threatening. The guidelines differ a little but in general, if the phlebitis is longer than 5 cm or within 3-5 cm of a deep vein, anticoagulation is advised.

Most patients with phlebitis are not at risk of PE’s. However without a duplex scan, it is impossible to tell which patients with Phlebitis are at risk and which patients are not.