Phlebitis most commonly affects the superficial veins in the legs. It is often caused by varicose veins. The inflamed vein is hard and painful and the skin above it is red. Various measures help to quickly alleviate the symptoms.

At a glance

  • A typical symptom of phlebitis is a blood vessel that feels hard and is painful when pressed. The skin above the vessel is red.
  • It is usually the veins in the legs that become inflamed. Varicose veins are often the cause of this.
  • Blood clots can form, which can lead to serious complications.
  • A medical examination is important if phlebitis is suspected.
  • Doctors can detect possible blood clots and their location using a special ultrasound examination.
  • Acute symptoms can usually be quickly alleviated.

Note: The information in this article cannot and should not replace a medical consultation and must not be used for self-diagnosis or treatment.

Person in a white coat palpating the bent calf of a patient lying on a treatment table.

What is phlebitis?

With phlebitis, in addition to the vein wall being inflamed, a blood clot (thrombus) often also forms that inhibits the blood flow in the vein. This is why superficial venous inflammation is also known as thrombophlebitis.

Although it is usually superficial leg veins that are inflamed, any veins can be affected. With supportive measures, the condition normally goes away again after a short time. If a blood clot forms and spreads to the deep vein system, this can lead to dangerous complications such as a pulmonary embolism.

What are the symptoms of phlebitis?

If a superficial vein becomes inflamed, a hard, sometimes knotty strand is formed under the skin, which hurts when pressed. The skin over the inflamed vein is reddened, swollen and very warm. People with phlebitis can also sometimes develop a slightly high temperature.

Phlebitis (superficial thrombophlebitis) produces a series of hard lumps underneath the skin that hurt when palpated.

Most inflammation disappears again without complication. However, complications can occur, for example if:

  • bacteria colonize the inflamed vein wall: the inflammation will then spread to the surrounding tissue. This can result in a high temperature and suppuration.
  • a blood clot spreads into deeper sections of the vein: deep vein thrombosis can ensue. The leg is swollen and the skin is often shiny and taut. The calves can be painful.
  • parts of a blood clot that has formed become detached: this can cause a pulmonary embolism, indicated by a sudden shortness of breath and chest pain.

Important: As complications caused by blood clots can have serious consequences, a doctor should always be consulted if phlebitis is suspected.

What causes phlebitis?

Up to 90 percent of cases of superficial venous inflammation are caused by varicose veins. Bulges in the vein wall cause the blood flow to swirl and slow. This leads to the formation of tiny blood clots (microthrombi), which trigger inflammation in the vein wall.

Up to 90 percent of cases of phlebitis (superficial thrombophlebitis) are caused by varicose veins.

If the inside of a blood vessel wall is no longer completely smooth due to inflammation, platelets accumulate there. This creates a blood clot that grows as more and more blood components settle on it. External injuries to the vein wall or access into the vein for an infusion (intravenous catheter) can also cause the formation of microthrombi and inflammation. A lack of physical exercise can also increase the risk of blood clots forming.

What factors increase the risk of phlebitis?

All factors that slow down the blood flow, increase blood clotting or change the inner blood vessel wall also increase the risk of superficial venous inflammation.

These include:

  • varicose veins
  • venous insufficiency
  • damage to the vein wall
  • surgery on veins
  • infusions via veins
  • injecting drugs into the veins

In general, blood clots are more common as a result of:

  • bed rest after surgery or due to other illnesses
  • too little exercise and physical activity
  • pregnancy and the postpartum recovery period
  • the use of hormonal contraceptives
  • hormone therapy during the menopause
  • changes to the blood clotting system that promote blood clotting
  • tumor diseases
  • severe obesity
  • older age
  • vasculitis
  • auto-immune diseases
  • previous incidences of phlebitis

How common is phlebitis?

It is estimated that between 5 and 8 of every 1,000 adult men and women develop superficial venous inflammation each year. The prevalence increases with age.

How does phlebitis progress?

Any discomfort caused by phlebitis usually disappears after a few days. In the case of uncomplicated inflammation without further risk factors, it is unlikely for complications to occur due to the formation and detachment of blood clots. However, it may still be possible to feel the thickened vein wall for several months.

With uncomplicated phlebitis, a follow-up medical examination about 7 to 10 days after the diagnosis can be useful to assess how the phlebitis is developing. If the phlebitis is caused by another condition, the outlook depends on how this is treated.

How is phlebitis diagnosed?

Phlebitis can be quickly diagnosed based on the typical symptoms and appearance. Despite this, doctors usually also perform a Doppler ultrasound to detect larger blood clots and their precise location. This also enables them to determine whether the blood clots are going away or developing further.

If the condition is without complications, no other examinations are required. If the phlebitis is thought to have potentially been caused by a blood clotting disorder, this can be checked by performing a blood test. Further investigations are predominantly offered if the patient has no varicose veins or if phlebitis recurs repeatedly.

How is phlebitis treated?

There are various ways to treat superficial venous inflammation. These primarily aim at alleviating the symptoms.

The methods include:

  • frequently raising the affected leg, but ideally not bed rest or immobilization
  • cooling or warming compresses
  • localized pressure treatment with compression stockings or bandages
  • non-steroidal anti-inflammatory drugs such as ibuprofen or diclofenac
  • antibiotics if there are signs of bacterial infection
  • anticoagulant drugs if there are signs or an increased risk of a larger blood clot

In rare cases, the affected vein may also be surgically removed or tied.

In cooperation with the Institute for Quality and Efficiency in Health Care (Institut für Qualität und Wirtschaftlichkeit im Gesundheitswesen – IQWiG).

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