Superficial venous thrombosis (superficial thrombophlebitis) is inflammation and clotting in a superficial vein.
Superficial venous thrombosis most often affects the superficial veins (located just under the skin) in the legs but may also affect superficial veins in the groin or in the arms. Superficial venous thrombosis in the arms usually results from having an intravenous catheter. Often, thrombosis occurs in people with varicose veins. However, most people with varicose veins do not develop thrombosis.
Even a slight injury can cause a varicose vein to become inflamed. Unlike deep vein thrombosis, which causes very little inflammation, superficial venous thrombosis involves a sudden (acute) inflammatory reaction that causes the thrombus (blood clot) to adhere firmly to the vein wall and lessens the likelihood that it will break loose. Unlike deep veins, superficial veins have no surrounding muscles to squeeze and dislodge a thrombus. For these reasons, superficial venous thrombosis rarely causes a blood clot to break loose (embolism).
Superficial venous thrombosis that repeatedly occurs in normal veins is called migratory phlebitis or migratory thrombophlebitis. It may indicate a serious underlying disorder, such as cancer of an internal organ. When migratory phlebitis and cancer of an internal organ occur together, the disorder is called Trousseau syndrome.
Symptoms and Diagnosis
Pain and swelling develop rapidly in the area of inflammation. The skin over the vein becomes red, and the area feels warm and is very tender. Because blood in the vein is clotted, the vein feels like a hard cord under the skin, not soft like a normal or varicose vein. The vein may feel hard along its entire length. The diagnosis is usually obvious to doctors just from examining the painful area. However, doctors must distinguish superficial venous thrombosis from an infection under the skin (cellulitis), which is treated differently.
Most often, superficial venous thrombosis subsides by itself. Applying warm compresses and taking an analgesic, such as aspirin or another nonsteroidal anti-inflammatory drug (NSAID—see Pain: Nonsteroidal Anti-Inflammatory Drugs), usually help relieve the pain. Although the inflammation generally subsides in a matter of days, several weeks may pass before the lumps and tenderness subside completely. To provide early relief, doctors may inject a local anesthetic, remove the thrombus, and then apply a compression bandage, which the person wears for several days. Sometimes people who have very extensive superficial venous thrombosis are also given heparin to help limit the blood's clotting.
Last full review/revision December 2012 by James D. Douketis, MD