If you are concerned about acute onset large veins on your legs, I recommend that you see a healthcare professional for formal evaluation. Varicose veins
are the result of dilation of the superficial venous system (great and small saphenous veins and their tributaries). The dilation results in dysfunction of the valves of the veins, which leads to non-laminar, turbulent and regurgitant flow that causes increased pressure on the veins resulting in dilation and regurgitant flow, resulting in venous hypertension. Varicose veins usually come on over several years once the capacity of the superficial vein valves is overcome. There can be multiple causes, some benign and others more severe. Given your history of acute onset, it is important to be seen by a healthcare professional to rule out concerning underlying causes. Varicose veins often run in families, and may be passed from generation to generation. Additionally, varicose veins often happen after childbirth due to the increased venous pressure associated with carrying a child. Concerning causes may result in acute onset. These may include May-Thurner syndrome, which is unilateral compression of the iliac vein resulting in rapid venous swelling in only the affect side. Deep venous thromboses, which affect the deep vein system may also cause varicose swelling and should be ruled out. Again, please speak with a healthcare professional.