Phlebitis: Definition, Causes, Symptoms, Treatment and Prevention

It is the name given to an inflammation of the veins, usually in the legs. It is almost always a complication of varicose veins.

Meaning of the word phlebitis

The word phlebitis is made up of two parts:

  1. “Phleb”: means “vein.”
  2. “Itis”: usually put at the end of a medical word to mean “inflammation.”

Therefore, “phlebitis” simply means inflammation in the veins. However, veins almost never become inflamed for no reason.

The most common cause of naturally occurring phlebitis is when a clot forms in a vein near the surface and the vein becomes inflamed, which is the natural reaction of a vein to a clot and the way clots are removed. of natural form.

Phlebitis of the legs

Now we will return to the most common type of phlebitis, the phlebitis that is associated with varicose veins or hidden varicose veins (caused by venous incompetence or venous reflux disease).

First of all, we must understand why the clot occurs in varicose veins or hidden varicose veins.

In normal leg veins, blood flows through the veins when it is pumped through the muscles of the feet or legs during exercise.

When the leg is not being exercised, blood begins to flow down the leg and is stopped by the valves. In people with varicose veins or hidden varicose veins (caused by venous incompetence or venous reflux disease) these valves have stopped working.

In this case, the blood is still pumped through the veins normally when moving. However, when the leg relaxes, the valves do not work and blood falls through the veins in the legs due to gravity.

The valves are said to be “incompetent” and the blood to “flow” down the veins in the legs in the opposite direction from normal.

This abnormal backward flow of blood increases the amount of blood in the leg veins and, once this backflow has been going on for several years, some of the vein walls weaken and begin to dilate.

If these enlarged veins are visible on the surface, they are called “varicose veins.” However, if they are too deep to be seen on the surface, they will not be visible. But they are there and they are dilated, so they act like any visible varicose vein.

Historically no names have been given to these veins.

We now call them “hidden varicose veins” for obvious reasons, and whenever we talk about hidden varicose veins, we know that they are caused by venous incompetence (valves do not work) and venous reflux disease (blood falls through the veins in opposite direction with gravity).


There are three causes and these are called ” Virchow’s Triad “. Virchow’s triad shows that blood will clot if any of the following occur:

  • There is a change in the wall of the glass.
  • There is a change in the flow of blood within the vessel.
  • There is a change in blood components.

In varicose veins and hidden varicose veins, both the vessel wall has changed due to dilation and also the flow has changed as the blood is now refluxing instead of being stopped by the normal valves.

As such, in certain circumstances, blood can clot within these varicose veins or hidden varicose veins.

When blood clots within a vein, it is called ” thrombosis .” When a thrombosis occurs within a vein, it irritates the wall, setting off a chain of events that results in inflammation of the vein wall and surrounding tissue.

This inflammation is nature’s way of trying to heal the clot or thrombosis. The inflammation increases the local blood supply and brings white blood cells to the area, which in the long term will destroy the clot.

However, in some patients, before this can happen, the clot can spread which can cause major problems. If the clot spreads to the deep veins, it can develop into a deep vein thrombosis (DVT).

Also, if that clot flies off in the venous bloodstream, it can travel through the heart and into the lungs, a very serious condition called pulmonary embolism (PE).

Until recently, it was thought that phlebitis couldn’t cause any major medical problems, so treatment was pretty simple: aspirin and compression stockings.

However, recent studies have shown that urgent duplex ultrasound is essential, and as a result, anticoagulant therapy may be necessary to stop deep vein thrombosis (DVT) and pulmonary embolism (PE).

It is very important to note at this point that the inflammation is due to a thrombosis (clot) within the vein and not to any infection. As we’ll see later, doctors and nurses who don’t understand phlebitis often prescribe antibiotics purely and simply because the vein is hot, tender, and red.

These are the signs of inflammation, which, in phlebitis, is due to healing and not infection. Therefore, antibiotics will have absolutely no effect on phlebitis.

Facts about phlebitis

Phlebitis is commonly misdiagnosed and most importantly, it is often poorly treated.

Essential Facts About Phlebitis

  • Phlebitis is due to blood clots in the superficial veins.
  • Antibiotics are not a treatment for phlebitis.
  • All people with phlebitis should have a duplex ultrasound.

Treatment is dictated by the results of the examination:

  • Anticoagulation (ie: warfarin ) if the clot is within 5 cm of the deep veins.
  • Asprine and support stockings if the clot is more than 5 cm from the deep veins.
Phlebitis can cause a clot to the lung if it is not treated correctly

According to studies, phlebitis in the veins of the legs can lead to clots that travel to the lungs. These clots are called Pulmonary Embolisms (PE) and can be life threatening.

Most phlebitis patients are not at risk for PE. However, without a duplex scan, it is impossible to determine which phlebitis patients are at risk and which are not.


Some symptoms that you may have are:

  • Hot veins.
  • Red colored veins.
  • Lumpy veins on the legs.

These are due to blood clots in the veins just below the surface. These clots cause the vein and surrounding tissues to swell. There is no infection, so antibiotics have no effect and should not be given.

The correct treatment depends on the amount of risk of developing pulmonary embolism (PE). This is evaluated by a duplex ultrasound, performed by specialists who treat the veins all the time.

It is essential that, if a diagnosis of leg phlebitis is made, a duplex ultrasound is performed as soon as possible to ensure that the correct treatment is initiated.

Also, the same duplex ultrasound will be able to diagnose the underlying cause of the phlebitis, usually varicose veins or hidden varicose veins.

Based on the results, a treatment plan can be put together to prevent phlebitis from reoccurring.


Treatment for superficial phlebitis may include removal of an IV catheter, warm compresses, or antibiotics if an infection is suspected.

To treat phlebitis, you may need to take blood thinners, which make it difficult for your blood to clot.

If the phlebitis is very extensive and causes significant problems with blood return to the limb, you may be a candidate for a procedure called a thrombectomy.

In this procedure, a surgeon inserts a lead and catheter into the affected vein and either removes the clot, dissolves it with clot-dissolving drugs, such as tissue plasminogen activators, or performs a combination of both.

Insertion of a filter into one of your main blood vessels, the vena cava, may be recommended if you have a DVT and are at high risk for pulmonary embolism, but cannot take blood thinners.

This filter will not prevent blood clots from forming, but it will prevent parts of the clot from traveling to your lungs.

Many of these filters are removable because permanent filters cause complications after being in place for a year or two.

These complications include:

  • Infection.
  • Life-threatening damage to the vena cava.
  • Enlargement of the blood vessels around the filter, allowing clots to pass through the filter into the lungs.
  • It coagulates up to, over, and beyond the filter within the vena cava, the latter of which can dislodge and travel to the lungs.

Minimizing your risk factors for developing future phlebitis will also be an important part of treatment.


If you are at risk of developing phlebitis, there are several ways you can take steps to prevent a blood clot from forming.

Some key prevention strategies include:

  • Discussing your risk factors with your doctor, especially before a surgical procedure.
  • Get up and walk around as soon as possible after surgery.
  • Wearing compression socks.
  • Stretching your legs and drinking lots of water when you travel.
  • Take medications as directed by your doctor, which may include blood thinners.