Usually there is thrombophlebitis, which is an inflammatory reaction around a thrombosed vein, presenting as a painful induration (thickening of the skin) with redness.

However, SVT can lead to serious complications (as well as signal other serious problems, such as genetic mutations that increase one's risk for clotting), and is therefore no longer regarded as a benign condition.

If the blood clot is too near the saphenofemoral junction there is a higher risk of pulmonary embolism, a potentially life-threatening complication.

SVT is recognized by the presence of pain, warmth, redness, and tenderness over a superficial vein.

[1] SVT in the lower extremities can lead to a dangerous complication in which the clot travels to the lungs, called pulmonary embolism (PE).

[3] However, because superficial veins lack muscular support, any clots that form are far less likely to be squeezed by muscle contraction, dislodged, and induce a PE.

[1] The optimal treatment for many SVT sites (i.e. upper limbs, neck, abdominal and thoracic walls, and the penis) has not been determined.

[1] Uninterrupted periods of sitting or standing may cause the SVT to elongate from its point of origin, increasing the risk for complications and clinical worsening.

[1] SVTs that occur within the great saphenous vein within 3 cm of the saphenofemoral junction are considered to be equivalent in risk to DVTs.

[3] NSAIDs (non-steroidal anti-inflammatory drugs) can be used in both oral or topical formulations for the relief of SVT symptoms.

[3] The British Committee for Standards in Haematology guidelines recommend the use of NSAIDs for low-risk SVTs (thrombus <4–5 cm in length, no additional risk factors for thromboembolic events).

[1] Surgical interventions are used for both symptomatic relief of the SVT as well as for preventing the development of more serious complications (e.g. pulmonary embolism).

[6] A Cochrane review recommends that future research investigate the utility of oral, topical, and surgical treatments for preventing the progression of SVTs and the development of thromboembolic complications.