Diagnosed with superficial thrombophlebitis, no trauma, common causes? is this dangerous? and after it heals does it usually reaccur?

Sometimes reaccures: Common causes of superficial thrombophlebitis include trauma, sedentary lifestyle, long periods of sitting like travel, varicose veins, obesity, may be painful but usually not dangerous as long as no extension into the deep venous system. Sometimes reaccures but most often in different viens.

Varicose veins: Usually associated with pre existing varicose veins of the leg. Generally benign but can recur.

Svt: could be related to venous insufficiency with varicoose veins oral contraceptives? recent airplane travel?