What Is Thrombophlebitis?

  • Geraint Duffy MSc, Medical Biotechnology and Business Management, University of Warwick, UK
  • N White Biochemistry, University of Surrey
  • Nick Gibbins BSc (Hons) Biochemistry, University of Sussex


Our blood travels through our bodies via a system of blood vessels known as our circulatory system. These blood vessels allow the oxygen and nutrients needed to stay alive to be pumped to distant parts of the body.1 Therefore, it is vital that these blood vessels do not become blocked or clogged, stopping blood from reaching distant body parts that rely on it to survive. 

Blood has the remarkable ability to form clots when you cut yourself to stop the bleeding. Although this ability stops you from bleeding out every time you cut yourself, sometimes these blood clots can form inside blood vessels, clogging them up. This is what happens in those with thrombophlebitis.2  

This article will cover: 

  • Types of thrombophlebitis
  • Causes
  • Symptoms
  • Diagnosis 
  • Treatment 
  • Prevention
  • Risks

Understanding thrombophlebitis

The circulatory system is responsible for carrying blood around the body via blood vessels. Arteries carry blood from the heart to other body parts, veins carry blood back to the heart while capillaries allow for blood to travel from arteries to veins while also supplying surrounding cells with oxygen and nutrients.1

Thrombophlebitis can be more easily understood by breaking down small sections of the word.2

  • Thrombo: Clotting of the blood to form a thrombus (blood clot attached to the inside wall of a blood vessel)
  • Phleb: Refers to veins
  • Itis: Inflammation

As a whole, thrombophlebitis refers to blood clots that form on the walls of veins, causing inflammation of the vein. The inflammation caused by the blood clot itself can block part of the vein, preventing blood flow back to the heart from that area in the body.2

There are two main types of thrombophlebitis:

Superficial Thrombophlebitis: Also known as Superficial Venous Thrombosis (SVT). Refers to blood clots within veins close to the skin.2

Deep Vein Thrombosis (DVT): Refers to blood clots within veins deep within the body. DVT most commonly affects veins deep within the thighs.3

Causes and risk factors

Thrombophlebitis can be caused by:

Trauma or Injury: Damage directly to veins or to the area around them can cause inflammation. This inflammation can result in a blood clot being formed on the wall of the vein.4

Prolonged Immobility: A lack of movement can result in thrombophlebitis due to reduced circulation. Remaining in bed or sitting for long periods slows down the blood circulating in your legs which can then clot within the veins.5

Genetic Disorders: Conditions with genetic mutations to proteins involved in blood clotting can make them more likely to form. These include mutations to Factor V Leiden, protein C, and protein S, all of which are involved in blood clot formation.6

Acquired Changes: Conditions such as infections, high blood pressure, cancer, diabetes, obesity, and heart disease have all been found to increase the chances of blood clots forming within blood vessels.2,3

Medical Procedures: In certain surgeries, having a catheter fitted or intravenous injections can cause inflammation within the veins, which can lead to blood clots forming on the vein walls.7

Varicose Veins: Swollen and enlarged varicose veins are due to damage or weakness to the walls or valves of the veins. These weaknesses increase the chances of blood clots forming on the vein walls. Roughly 75% of superficial thrombophlebitis cases are in people with varicose veins.8

Dehydration: Being dehydrated can cause the blood to thicken, increasing the chances of clots forming within blood vessels.9


Symptoms differ slightly between the two types of thrombophlebitis. Common symptoms between the two are usually restricted to the area where the clot has formed and include:2,3

  • Pain 
  • Redness
  • Swelling
  • Tenderness
  • Skin hotness

DVT usually has worse symptoms compared to superficial thrombophlebitis, such as larger areas of swelling or the area feeling even more tender and painful. DVT may also cause fevers as well as cause the skin near the area affected to turn blue-purple in colour (cyanosis).3

These are common symptoms in thrombophlebitis, however, some people may only have some of these symptoms or even, not have any symptoms at all.


There are three different methods of diagnosis for thrombophlebitis. Combinations of these fields allow for ruling out similar conditions,  pinpointing the cause as thrombophlebitis. These include: 

Physical examination

Involves a doctor looking at the affected area and asking about a history of any symptoms you may have experienced before. From here, the doctor can order clinical tests to investigate further.2,3

Imaging tests

The main test used in diagnosing thrombophlebitis is ultrasound testing. This creates an image of the area affected using sound waves to find any blood clots present as well as where they are. Because of this, ultrasound testing can tell if you have superficial thrombophlebitis or DVT.2,3

Blood tests

When blood clots break down, they release a protein called D-dimer, which can be measured by blood tests. D-dimer levels can tell if a blood clot formed within a vein before breaking down. D-dimer testing differentiates between the two types of thrombophlebitis, but it is useful in showing if you may be at increased risk of further blood clots forming.10


Thrombophlebitis can lead to other serious health conditions, with DVT more likely to cause these conditions. However, a history of superficial thrombophlebitis can later lead to DVT.2 These conditions include:

Pulmonary embolism

Blood clots can dislodge from the wall of the vein and are then free to travel through the vein, becoming an embolism. Embolisms can travel to distant blood vessels that are narrower, where they can block them and stop blood flow from travelling any further. 

This can happen in the arteries leading into the lungs, blocking blood from reaching the lungs. This is known as a Pulmonary Embolism and can be fatal if not treated.11

Post-thrombotic syndrome

The clots formed within the deep veins can cause damage to the veins themselves, impairing the valves within that stop blood from flowing backwards. This causes blood to pool in the vein, putting pressure on the vein wall. Even after the clot has been broken down, the damage to the vein wall can leave lasting effects such as swelling, pain, thickening of the skin, and muscle tiredness, which can last up to 2 years.12

Treatment options

Treatment can depend on the type of thrombophlebitis, where the affected vein is, and the cause of the clot. Treating thrombophlebitis includes:2,3

  • Painkillers - Reduce pain and tenderness
  • Anticoagulants - Medications that stop other blood clots from forming. These include medications such as rivaroxaban and fondaparinux.
  • Compression stockings - Help improve circulation in the legs, reducing the chances of other clots forming
  • Warm water compress/heating pad - Help alleviate swelling and tenderness
  • Antibiotics - Treat the infection, causing blood clots to form.

Superficial thrombophlebitis treatment usually lasts for around a month but can be 2–3 months long to stop other blood clots from forming.2 Treatment of DVT will usually last between 3–6 months but could also last as long as 12 months.3

Surgery can also be used to treat people with DVT with the placement of an Inferior Vena Cava (IVC) Filter. This involves placing a metal filter into the vena cava, a large vein that leads from the lower body up to the heart. The filter stops any blood clots that may break loose from travelling to the lungs, preventing pulmonary embolisms.13


The chances of developing thrombophlebitis can be reduced by making positive changes to your lifestyle. These can directly reduce the chances of blood clots forming or can help with other causes of thrombophlebitis, such as obesity, high blood pressure, heart disease, and diabetes.2,3 These changes can include:

  • Keeping hydrated
  • Taking breaks to get up and move around after sitting in place for long periods
  • Healthy changes to your diet
  • Lowering your blood pressure
  • Quitting smoking
  • Getting regular exercise


For those who are at a higher risk of thrombophlebitis, such as those with varicose veins or other linked conditions, anticoagulant medication may be given to reduce the chance of clots forming.2,3

Living with thrombophlebitis

For those who have already been diagnosed with thrombophlebitis, the chances of having other blood clots are increased. Because of this, it is important to help reduce this risk. By tackling conditions such as obesity, high blood pressure, and diabetes, which are linked to thrombophlebitis, this risk can be reduced.2,3

It is also important to keep up with any medication given by the doctor, as this can also reduce the risk of other clots forming. Any follow-up appointments should be attended as these can help find and treat other problems early.

For those with thrombophlebitis or who have family or friends with the condition, help and advice can be found in organisations such as Thrombosis UK and Circulation Foundation.


To summarise, thrombophlebitis is when blood clots form within veins, causing inflammation. There are two types: superficial thrombophlebitis and deep vein thrombosis. It can be caused by damage to the veins themselves from injuries or medical procedures, conditions such as genetic disorders, obesity, infections, cancer, and high blood pressure, or staying in place for long periods of time.

Thrombophlebitis usually affects the legs with signs including swelling, pain, and redness but can also cause the area to turn blue-purple. These symptoms are checked by a doctor who can diagnose thrombophlebitis with ultrasound and blood tests.

Painkillers and anticoagulant medication are commonly used to treat the condition but treatment can also include heat pads, compression stockings, and in certain circumstances, surgery. If untreated, thrombophlebitis can lead to dangerous complications such as post-thrombotic syndrome and pulmonary embolism.


  1. Chaudhry R, Miao JH, Rehman A. Physiology, cardiovascular. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 [cited 2023 Oct 6]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK493197/.
  2. Czysz A, Higbee SL. Superficial thrombophlebitis. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 [cited 2023 Oct 6]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK556017/.
  3. Waheed SM, Kudaravalli P, Hotwagner DT. Deep vein thrombosis. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 [cited 2023 Oct 6]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK507708/.
  4. Nielsen S, O’Connor D, Kaul S, Sharma J, Napolitano M, Simonian G, et al. Early detection of deep venous thrombosis in trauma patients. Cureus [Internet]. [cited 2023 Oct 6];12(7):e9370. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7444965/.
  5. Liu Z, Tao X, Chen Y, Fan Z, Li Y. Bed rest versus early ambulation with standard anticoagulation in the management of deep vein thrombosis: a meta-analysis. PLoS One [Internet]. 2015 Apr 10 [cited 2023 Oct 6];10(4):e0121388. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4393252/.
  6. Khan S, Dickerman JD. Hereditary thrombophilia. Thromb J [Internet]. 2006 Sep 12 [cited 2023 Oct 6];4:15. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1592479/.
  7. Evans NS, Ratchford EV. Catheter-related venous thrombosis. Vasc Med [Internet]. 2018 Aug [cited 2023 Oct 6];23(4):411–3. Available from: http://journals.sagepub.com/doi/10.1177/1358863X18779695.
  8. Tait C, Baglin T, Watson H, Laffan M, Makris M, Perry D, et al. Guidelines on the investigation and management of venous thrombosis at unusual sites. Br J Haematol [Internet]. 2012 Oct [cited 2023 Oct 6];159(1):28–38. Available from: https://onlinelibrary.wiley.com/doi/10.1111/j.1365-2141.2012.09249.x.
  9. Shbeer A. Extensive lower limb deep vein thrombosis provoked by gastroenteritis-induced dehydration: a case report for unusual precipitating factor. Int Med Case Rep J [Internet]. 2022 Dec 6 [cited 2023 Oct 6];15:713–8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9739949/.
  10. Bounds EJ, Kok SJ. D dimer. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 [cited 2023 Oct 6]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK431064/.
  11. Tarbox AK, Swaroop M. Pulmonary embolism. Int J Crit Illn Inj Sci [Internet]. 2013 [cited 2023 Oct 6];3(1):69–72. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3665123/.
  12. Kahn SR. The post-thrombotic syndrome. Hematology Am Soc Hematol Educ Program [Internet]. 2016 Dec 2 [cited 2023 Oct 6];2016(1):413–8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6142466/.
  13. Muneeb A, Dhamoon AS. Inferior vena cava filter. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 [cited 2023 Oct 6]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK549900/.
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Geraint Duffy

Master of Science - MSc, Medical Biotechnology and Business Management, University of Warwick

Recently graduating from my postgraduate degree, my interest in medicines and how they function has led me to pursue a pharmaceutical regulation career. I have experience researching how obstructive sleep apnoea is linked with the development of dementia and how specific genetic mutations can change the effectiveness of diabetic medications.

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