Superficial Thrombophlebitis is a medical condition characterized by inflammation with the formation of a blood clot in a vein that is located near the skin (a superficial vein). It usually occurs in the leg, but may also happen in the arm or neck. It is commonly due to prolonged intravenous use, injury, surgery or long periods of sitting. When the vein is inflamed, it causes signs and symptoms, such as redness, warm and pain on the skin of the affected area. Superficial thrombophlebitis is a mild condition. Symptoms generally disappear within 1 to 2 weeks without any complications with treatment. In very rare cases, complications, such as gangrene, cellulitis and pulmonary embolism may occur.