Figure 1

Superficial veins lie above the muscles of the leg. They are the saphenous veins and their branches. Superficial venous thrombophlebitis (SVT) is inflammation in addition to a blood clot, in a superficial vein or veins that lie above the muscles of the leg and in the fatty tissue just under the skin (Figure 1). SVT is a common disorder with a potential for extension into a deep vein and for pulmonary embolism  (blood clot in the lung). About 35-46% of persons affected are men, average age 54 years. The average age for women with SVT is 58.

Figure 1. Superficial venous thrombosis with localized tenderness and swelling surrounding a thrombosed superficial vein.  (Awaiting adaptation from DeWeese JA. In Schwartz SI, ed. Venous and Lymphatic Disease:Principles of Surgery, 4th ed. New York: McGraw-Hill, 1984.)

The most common predisposing risk factor for SVT is the presence of varicose veins (in 62%). Varicose veins are dilated, distended veins lying under the skin and within the fatty tissue of the leg. Other risk factors are age over 60, obesity, tobacco use, and a history of deep venous thrombosis or of prior SVT. Diagnosis is based on the presence of red streaking in the area of distribution of the superficial veins and tenderness around the thrombus (clot). Pain, warmth, and swelling are usually present.