Phlebitis: Phlebitis is the inflammation of a vein. Superficial phlebitis affects the veins on the surface of the skin. Deep vein thrombophlebitis affects the larger veins deep in the veins. Blood clots in the legs can form from deep vein thrombophlebitis and potentially lead to pulmonary embolism. Causes of phlebitis include sedentary lifestyle, smoking, varicose veins, cancer, hormone therapy, birth control pills, obesity, or injury to the legs or arms. Symptoms of phlebitis include red, tender, warm, hard, throbbing, or burning feeling along the skin. Fever, may sometimes be present. Treatment depends on the location and severity of the condition.