Initial assessment
When a patient presents with suspected superficial venous thrombosis, also known as superficial thrombophlebitis, it is essential to assess predisposing factors. These include vascular factors, such as local trauma or venous puncture; venous stasis associated with varicose veins, chronic venous insufficiency, pregnancy or prolonged immobilisation; and prothrombotic states, such as malignancy, thrombophilia or hormone therapy.
Migratory, recurrent or multifocal thrombophlebitis should raise suspicion of occult malignancy, particularly pancreatic adenocarcinoma, and further investigation should be guided by the clinical context.
Suggestive clinical findings
The diagnosis is often suggested clinically. A firm, palpable superficial venous cord should be sought, usually tender or painful and following the course of the vein. The adjacent skin may be warm and erythematous, with mild local swelling. When there is marked or diffuse swelling of the entire limb, associated deep vein thrombosis should be considered.
Role of venous Doppler ultrasound
Venous Doppler ultrasound is the reference imaging test for confirming superficial venous thrombosis, assessing its extent and excluding deep vein thrombosis. In selected cases of clearly localised SVT affecting a varicose vein below the knee, without risk factors for extension or venous thromboembolism, Doppler ultrasound may not be necessary.
However, it should be performed particularly when there is diagnostic uncertainty, suspected DVT, thrombosis above the knee, involvement of the upper third of the thigh or popliteal region, extensive thrombosis or relevant predisposing factors.
Exclusion of deep vein thrombosis
If Doppler ultrasound identifies associated deep vein thrombosis, management should follow the specific recommendations for DVT, with therapeutic-dose anticoagulation for a duration adjusted to the clinical context.
Thrombus location and extent
Once superficial venous thrombosis has been confirmed, treatment decisions depend mainly on its location, extent and proximity to the deep venous system. The distance from the saphenofemoral junction is particularly important.
When the thrombus is less than 3 cm from the saphenofemoral junction, it should be treated in a similar way to DVT because of the risk of extension into the deep venous system.
Indications for anticoagulation
When the thrombus is 3 cm or more from the saphenofemoral junction, anticoagulation is generally indicated if the thrombosis extends for more than 5 cm, symptoms are severe or risk factors for thrombotic extension are present.
These factors include a previous history of DVT, active malignancy, pregnancy or the postpartum period, hormone therapy, recurrent SVT, absence of varicose veins, known thrombophilia, systemic inflammatory disease, and recent trauma or surgery.
Anticoagulant treatment options
When prophylactic-dose anticoagulation is indicated, the usual recommended duration is 45 days. Options include fondaparinux 2.5 mg subcutaneously once daily, rivaroxaban 10 mg orally once daily, or low-molecular-weight heparin at a prophylactic or intermediate dose.
The choice should be individualised according to bleeding risk, renal function, comorbidities, patient preferences and treatment availability.
Symptomatic treatment
In less extensive cases, localised to a distal varicose vein and without risk factors for progression, treatment may be symptomatic only. Topical or oral non-steroidal anti-inflammatory drugs may be used for 7 to 14 days. Examples include ibuprofen 400 mg three times daily or naproxen 500 mg twice daily, provided there are no contraindications.
Limb elevation and compression stockings may be considered as adjunctive measures for symptom relief, particularly in patients with varicose veins or chronic venous insufficiency.
Differential diagnosis
When Doppler ultrasound does not confirm superficial or deep venous thrombosis, alternative diagnoses should be considered, including cellulitis, erysipelas, erythema nodosum, ruptured Baker’s cyst, haematoma, lymphangitis or superficial venous insufficiency.
Follow-up
Reassessment is important if symptoms worsen, there is no improvement after 7 to 14 days, the thrombosis extends proximally or signs suggestive of DVT develop. The duration and intensity of anticoagulation should be adjusted to the patient’s individual characteristics and the location of the thrombus.
Conclusion
Superficial venous thrombosis is often benign, but in higher-risk situations it may be associated with deep vein thrombosis or pulmonary embolism. A structured approach based on thrombus location, extent and risk factors for progression enables appropriate selection of patients who may benefit from symptomatic treatment, Doppler ultrasound or anticoagulation.
