Deep vein thrombosis (DVT) is a blood clot that forms inside a vein deep in the body, whereas superficial thrombophlebitis (STP) is inflammation of the veins just below the skin’s surface. STP can occur due to a blood clot in a superficial vein.

DVT is a medical emergency. Without immediate treatment, it may lead to severe complications or even sudden death.

In contrast, STP may resolve without the need for medical treatment. However, it may also increase the risk of developing DVT. If a person has symptoms of DVT or STP, it is best to seek medical help.

This article compares the symptoms and causes of DVT and STP, outlines their treatments and outlooks, and provides tips on how to help prevent blood clots.

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The following sections outline the potential symptoms of DVT and STP.

DVT symptoms

DVT can develop in any of the body’s deep veins, but it typically develops in deep veins in the pelvis, thigh, or calf.

According to the American Academy of Orthopaedic Surgeons (AAOS), DVT often does not cause symptoms. However, when symptoms do occur, they affect the part of the body where DVT occurs.

DVT in the leg may cause the following symptoms in that leg:

For some people, a pulmonary embolism may be the first sign of DVT. This is a blood clot in the lung and may cause the following symptoms:

STP symptoms

According to the United Kingdom’s National Health Service (NHS), STP usually affects the superficial veins in the legs but can also affect the superficial veins of the arms or neck.

STP may cause the following symptoms in the affected part of the body:

  • pain, tenderness, or swelling
  • warmth and itchiness
  • changes to skin color, such as redness
  • changes to skin texture, such as thickness or hardness
  • firmness or thickening of the vein called a “cord” that a person may be able to feel

Below are some causes of DVT and STP, as well as some of the risk factors associated with each of these conditions.

DVT risk factors

DVT forms when blood flow within one of the body’s deep veins slows or stops. According to the Centers for Disease Control and Prevention (CDC), some factors that can increase the risk include:

STP risk factors

According to the NHS, STP does not always have a clear cause. Inflammation may occur due to:

  • varicose veins, which are swollen, enlarged veins
  • conditions that cause the blood to clot more easily, such as thrombophilia
  • autoimmune conditions that cause inflammation of the blood vessels, such as Behçet’s disease
  • receiving injections into a vein or having an intravenous (IV) line in a vein

Other risk factors for STP include:

  • having a prior history of phlebitis
  • aging
  • obesity
  • pregnancy
  • cancer

Below are the different treatment approaches for DVT and STP.

DVT treatment

According to the AAOS, DVT treatment aims to prevent the clot from getting larger, minimize the risk of complications, such as a pulmonary embolism, and reduce the risk of other clots.

Treatment options include:

  • Observation and monitoring: If the DVT is in the lower part of the leg, a doctor may recommend observation and monitoring using a series of ultrasound scans.
  • Anticoagulant medications: These medications help dissolve existing blood clots and prevent further clotting. Examples include:
    • direct oral anticoagulants (DOAC)
    • heparin
    • low molecular weight heparin
    • warfarin (Coumadin)
  • Thrombolytics: These are medications that a doctor injects directly into a blood clot to help dissolve the clot. Doctors may use thrombolytics in cases where there is a very high risk of pulmonary embolism.
  • Surgical options: This may include surgery to remove a blood clot from the veins or lungs or surgery to fit a device called a vena cava filter, which captures blood clots traveling to the lungs.

Nonsurgical DVT treatments are the most common. However, doctors may recommend surgical treatment for DVT in cases where anticoagulants are ineffective or a person is unable to take anticoagulants.

STP treatment

According to the NHS, STP that causes only mild symptoms may not require treatment.

However, severe or persistent STP may require treatments such as:

The outlooks for those with DVT and STP differ, with DVT presenting the greatest risk to health.

DVT outlook

According to the CDC, between 60,000 and 100,000 Americans die of DVT every year, with sudden death being the first symptom in approximately 25% of cases.

Of those who survive DVT, around 1 in 3 will experience long-term complications. The most severe is a pulmonary embolism. Another is a condition called post-thrombotic syndrome (PTS).

PTS develops in roughly 1 in 3 people who survive DVT. The condition occurs due to clot-induced damage to the valves within the vein. Symptoms develop in the affected body part and may include:

The CDC also estimates that 1 in 3 people who survive the initial DVT will experience DVT again within 10 years.

STP outlook

According to the NHS, STP is not typically a medical emergency and usually resolves without treatment within 1–2 weeks.

However, a 2017 review notes that STP often occurs alongside asymptomatic DVT. Therefore, the reviewers recommend that all individuals presenting with STP symptoms receive an ultrasound scan to check for DVT.

According to the review, STP can also progress to DVT in some cases. The authors recommend that individuals at risk of developing DVT receive low dose anticoagulant medications as a preventive measure.

The American Heart Association (AHA) recommends strategies for helping prevent blood clots in high risk situations, such as during periods of inactivity due to surgery, hospitalization, or long-distance travel.

Methods to help prevent blood clots include:

  • making an effort to move around if possible
  • wearing compression devices
  • taking prescription medications
  • performing exercises, such as:
    • flexing and extending the ankles
    • contracting the calf muscles
  • changing positions regularly
  • staying hydrated

It is best to contact a doctor as soon as possible if a person develops symptoms of STP. Although STP is rarely dangerous, research suggests that it can occur alongside DVT or progress to DVT.

Anyone who develops symptoms of DVT should seek emergency medical care immediately. DVT is a life threatening condition that can lead to sudden death. Emergency medical treatment with anticoagulation medication can save a person’s life.

Potential DVT symptoms to look out for include:

  • throbbing or cramping pain in the leg, arm, or neck
  • sudden swelling in the leg, arm, or neck
  • swollen veins that are hard or sore to the touch
  • warm, red, or darkened skin around the painful area

Deep vein thrombosis (DVT) and superficial thrombophlebitis (STP) are conditions of the circulatory system. DVT is a blood clot that forms in a deep vein, whereas STP is inflammation of the superficial veins close to the skin’s surface.

STP is typically not a medical emergency. However, research suggests that STP may increase a person’s risk of developing DVT. Anyone who experiences symptoms of STP should speak with their doctor for a thorough medical evaluation.

DVT is a medical emergency. Anyone who experiences symptoms should phone the emergency services immediately. Prompt treatment with anticoagulant medications or surgery can help prevent complications, including death.