Superficial Thrombophlebitis

Superficial vein thrombosis (SVT) sits on the VTE spectrum. It is not a benign, self-limiting complaint. Approximately 20–25% of patients with SVT are found to have concomitant venous thromboembolism (DVT or PE) at diagnosis.

Common in malignancy, pregnancy, IV cannulation, and varicose veins. Varicose veins are present in up to 80% of SVT cases.

History

Timing, location, pain, redness. History of malignancy, IV cannulation, or varicose veins. Current pregnancy. Recent travel or surgery. Shortness of breath and chest pain (screen for associated VTE).

Other risk factors: obesity, immobility, oestrogen therapy (COC, MHT), thrombophilia, personal or family history of VTE, age over 60, smoking, and inflammatory disease such as lupus.

Think of cancer in two situations:

• A first presentation of SVT in patients aged over 40 years, particularly in the absence of known risk factors, should prompt consideration of an underlying malignancy.
• Recurrent or migratory thromboses at different sites over time (Trousseau syndrome).

Examination

It usually appears as an area of erythema and surrounding the occlusion of a superficial vein, with a tender palpable cord. The great saphenous vein is the most common site.

Check Temperature, BP, and pulse to assess for associated systemic infection.

Assess for evidence of VTE — marked by the presense of unilateral limb swelling or a firm limb on palpation. Oxygen saturation at rest and on exertion, chest auscultation.

Mimics: cellulitis, lymphangitis, vasculitis.

Investigations

Consider venous ultrasound to rule out an associated DVT if indicated. Duplex ultrasound is the definitive test. Get one in most patients, particularly if the SVT is proximal or atypical, or there are VTE risk factors.

For isolated distal SVT confined to varicose veins without risk factors, a clinical diagnosis may suffice. D-dimer testing has no role in SVT diagnosis.

Ask the ultrasound report to state:

• which vein, and whether the thrombus is acute or chronic
• thrombus length
• distance from the saphenofemoral (SFJ) and saphenopopliteal (SPJ) junctions
• any DVT (contiguous or separate) and any propagation.

If concerned about PE, use Wells’ criteria to guide investigation — see Chest Pain for the Wells score and PERC rule.

Risk stratification

Risk	Ultrasound and patient features	Management
Low	<5 cm long, >3 cm from SFJ/SPJ, no other risk factors	Symptomatic care, no anticoagulation
Intermediate	≥5 cm long, or 3–5 cm from a junction, no systemic risk factors	Prophylactic-dose anticoagulation, 45 days
High	≤3 cm from a junction, propagation, recurrent SVT, thrombophilia or malignancy	Therapeutic anticoagulation, 3 months

Management

Antibiotics are not indicated unless the patient has cellulitis or sepsis. Both low molecular weight heparin and NSAIDs reduce the incidence of extension or recurrence by about 70% compared with placebo.

Low risk

• Topical or oral NSAID (ibuprofen or diclofenac) for 7–14 days.
• Elevation, compression stockings (exclude significant arterial disease first), keep walking, warm or cool compresses.
• If symptoms persist or worsen following conservative management, repeat clinical examination and follow-up duplex ultrasonography within 2–3 days are recommended.

Intermediate risk — prophylactic dose for 45 days

• Fondaparinux 2.5 mg SC once daily has the strongest trial evidence (CALISTO) and is PBS-listed.
• Rivaroxaban 10 mg once daily for 45 days is non-inferior to fondaparinux (SURPRISE). Avoid if CrCl <30 mL/min.
• For spontaneous superficial thrombophlebitis (especially thigh vein involvement), consider enoxaparin 40mg (20mg if CrCl < 30mL/min) SC daily for 4–6 weeks. Doses of 40–80 mg daily are used.

High risk — therapeutic dose for 3 months

Treat as for DVT. Patients with a thrombus up to 3 cm from the SFJ should be treated for DVT, given that 14–70% progress to DVT.

• Apixaban 10 mg twice daily for 7 days, then 5 mg twice daily. Not trialled in SVT itself, but it caused less bleeding than rivaroxaban in acute VTE (COBRRA).
• Rivaroxaban 15 mg twice daily for 21 days, then 20 mg once daily.
• Enoxaparin 1 mg/kg twice daily or 1.5 mg/kg once daily.

See Anticoagulation & VTE Treatment.

Upper limb and cannula-related SVT

• If a complication of an IV infusion — consider topical or oral NSAID.
• These are usually short and isolated. Remove the cannula and use warm compresses and NSAIDs.
• Anticoagulate only if the thrombus is extensive, symptomatic beyond the cannulated segment, or the patient has high thrombotic risk.
• Suppurative thrombophlebitis (local or systemic signs of infection) needs antibiotics.

Special populations

• Pregnancy: Direct oral anticoagulants (DOACs) are contraindicated during pregnancy. Use LMWH, eg enoxaparin 40–80 mg daily for 1–6 weeks. Get specialist input if the thrombus is ≥5 cm, bilateral, or not settling. For patients not receiving anticoagulants, serial duplex ultrasonography every 7–10 days is recommended.
• Active cancer: Patients with active cancer should be given anticoagulation therapy for a minimum of 45 days.
• Renal impairment: avoid rivaroxaban if eGFR <30. Adjust the enoxaparin dose and seek specialist input.

Referral

Vascular surgery or haematology for:

• recurrent or propagating SVT despite anticoagulation
• thrombus within 3 cm of a deep vein not resolving on treatment
• SVT with active malignancy, or suspected thrombophilia
• an atypical site or unclear ultrasound
• anticoagulation needed beyond 45 days (intermediate) or 3 months (high risk).

Surgical options such as vein ligation or ablation are typically delayed ≥3 months after the acute phase.

Follow-up

• Continue to monitor for VTE.
• Follow-up duplex ultrasonography within 7–10 days is recommended in intermediate- and high-risk cases, or if symptoms progress, to monitor for propagation.
• Counsel on DVT and PE symptoms (unilateral leg swelling, chest pain, breathlessness) and the ongoing risk of recurrence.
• Discuss compression stockings and treatment of varicose veins.