Clot forming in the veins of the skin or fatty tissues of the extremities is called superficial venous thrombosis (SVT). Symptoms often involve a tender lump under the skin at the location of a vein with a pink color in the skin overlying the thrombus. Superficial thrombus rarely is life-threatening since it usually forms in veins which are small. Any thrombus which migrates from small veins in the circulation is unlikely to significantly block flow in the veins of the lungs. However, 20% of patients who develop SVT will also be found to have extension of the thrombus into the deep veins of the extremity (DVT) which is a much more serious condition. For this reason, venous color duplex ultrasound examinations frequently are employed to evaluate the extent of the thrombus.

The most common cause of SVT is varicose veins which are enlarged and result in slow blood flow through the varicose veins. Slowly moving blood is prone to clot within the varicose veins.

Any of the disorders which increase the risk of clotting will increase the risk of SVT. Patients who develop SVT unrelated to varicose veins or in multiple different locations need to be evaluated for causes of the SVT which require treatment to prevent reoccurrence of SVT, development of DVT, or progressive health problems.

SVT in the lower extremities is treated with elastic compression hose and local comfort measures such as warm compresses. The pain associated with SVT usually improves considerably over a few days through local swelling and tenderness may last many months.

SVT in large veins such as the great saphenous vein in the upper thigh often has been treated with drugs to prevent formation of more thrombus with anticoagulants such as low molecular weight heparin injections or oral anticoagulants such as warfarin. While still controversial, many physicians are treating SVT in some smaller veins with anticoagulant drugs as well.

Anti-inflammatory drugs such as aspirin, ibuprofen, or naproxen help with the symptoms of pain and tenderness and reduce the inflammatory process surrounding the vein.