Phlebitis is the inflammation of a vein. Veins are blood vessels in your body that carry blood from your organs and limbs back to your heart.

If a blood clot is causing the inflammation, it’s called thrombophlebitis. When the blood clot is in a deep vein, it’s called deep vein thrombophlebitis, or deep vein thrombosis (DVT).

Phlebitis can be superficial or deep.

Superficial phlebitis refers to the inflammation of a vein near the surface of your skin. This type of phlebitis may require treatment, but isn’t usually serious. Superficial phlebitis can result from a blood clot or from something causing irritation, such as an intravenous (IV) catheter.

Deep phlebitis refers to inflammation of a deeper, larger vein, such as those found in your legs. Deep phlebitis is more likely to be caused by a blood clot, which can have very serious, life-threatening consequences. It’s important to know the risk factors and symptoms of a DVT so that you can seek prompt attention from your doctor.

Symptoms of phlebitis affect the arm or leg where the inflamed vein is located. These symptoms include:

  • redness
  • swelling
  • warmth
  • visible red “streaking” on your arm or leg
  • tenderness
  • rope- or cord-like structure that you can feel through the skin

You may also notice pain in your calf or thigh if your phlebitis is caused by a DVT. The pain may be more noticeable when walking or flexing your foot.

Only about half of those who develop a DVT experience symptoms. This is the reason that DVTs may not be diagnosed until a serious complication occurs, such as a pulmonary embolism (PE).

Superficial thrombophlebitis usually doesn’t result in serious complications. But it can lead to infection of the surrounding skin, wounds on the skin, and even bloodstream infections. If the clot in the superficial vein is extensive enough and involves the area where the superficial vein and a deep vein come together, 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:

Call your local emergency services if you think you may be experiencing a PE. This is a medical emergency that requires immediate treatment.

Phlebitis is caused by injury or irritation to the lining of a blood vessel. In the case of superficial phlebitis, this may be due to:

  • placement of an IV catheter
  • administration of irritating medications into your veins
  • a small clot
  • an infection

In the case of DVT, the causes may include:

  • irritation or injury of a deep vein due to trauma such as surgery, a broken bone, serious injury, or previous DVT
  • slowed blood flow due to lack of motion, which may occur if you’re in bed recovering from surgery or traveling for a long period of time
  • blood that is more likely to clot than usual, which may be due to medications, cancer, connective tissue disorders, or inherited blood clotting conditions

Knowing if you have risk factors for developing a DVT is key to protecting yourself and proactively developing a plan with your doctor. Risk factors for DVT typically include:

  • a history of DVT
  • blood clotting disorders, such as factor V Leiden
  • hormone therapy or birth control pills
  • prolonged periods of inactivity, which may follow surgery
  • sitting for long periods of time, such as during travel
  • certain cancers and cancer treatments
  • pregnancy
  • being overweight or obese
  • smoking
  • misusing alcohol
  • being over the age of 60

Phlebitis can be diagnosed based on your symptoms and an exam by your doctor. You may not need any special tests. If a blood clot is suspected as the cause of your phlebitis, your doctor could perform several tests in addition to taking your medical history and examining you, however.

Your doctor may order an ultrasound of your affected limb. An ultrasound uses sound waves to show the flow of blood through your veins and arteries. Your doctor may also want to assess your d-dimer level. This is a blood test that checks for a substance released in your body when a clot dissolves.

If the ultrasound doesn’t provide a clear answer, your doctor may also perform a venography, a CT scan, or an MRI scan to check for the presence of a blood clot.

If a clot is detected, your doctor may want to take blood samples to test for blood clotting disorders that could have caused the DVT.

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

To treat DVT, you may need to take anticoagulants, which make it harder for your blood to clot.

If the DVT is very extensive and causing significant problems with blood return in the limb, you may be a candidate for a procedure called a thrombectomy. In this procedure, a surgeon inserts a wire and catheter into the affected vein and either removes the clot, dissolves it with medications that break up the clot, such as tissue plasminogen activators, or performs a combination of both.

Insertion of a filter into one of your major blood vessels, the vena cava, may be recommended if you have a DVT and are at high risk for pulmonary embolism but can’t take blood thinners. This filter won’t prevent blood clots from forming, but it will prevent pieces of the clot from traveling to your lungs.

Many of these filters are removable because permanent filters cause complications after being in place for one to two years. These complications include:

  • infection
  • life-threatening damage to the vena cava
  • enlargement of blood vessels around the filter, which allows clots to pass by the filter and into the lungs
  • clots up to, on, and past the filter within the vena cava, the latter of which can break off and travel into the lungs

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

If you’re at risk for developing a DVT, there are a number of ways you can take action to prevent a blood clot from forming. Some key prevention strategies include:

  • discussing your risk factors with your doctor, especially prior to a surgical procedure
  • getting up and walking as soon as possible after surgery
  • wearing compression socks
  • stretching your legs and drinking plenty of water when traveling
  • taking medications as instructed by your doctor, which may include blood thinners

Superficial phlebitis often heals without lasting effects.

DVT, on the other hand, can be life-threatening and requires immediate medical attention. It’s important to know if you have risk factors for developing a DVT and to receive regular medical attention from your doctor.

If you’ve experienced a DVT before, you may be more prone to experiencing another in the future. Taking proactive steps may help prevent DVT.