Varicose veins are thick "blue veins" on the legs with prominent twists and turns. Due to congenital reasons, weight bearing, pregnancy and other factors that can cause the increase of venous pressure, the venous valve of lower limbs is relaxed and venous blood returns. In the long run, the pressure on superficial veins will increase, and the so-called "blue veins bulge" will gradually appear in appearance.

Some patients can form thrombus in varicose superficial vein, which shows local redness and pain, hard mass formation, and pain affects walking. If not treated in time, thrombus may spread upward or spread to deep vein through communicating vein, leading to deep vein thrombosis, which is life-threatening together with pulmonary embolism. It is recommended to go to a regular hospital for treatment as soon as possible.