If you have underlying venous disease (e.g., venous reflux), the pressure created by backflow of blood and pooling in the lower legs may create a progressive condition that only gets worse with time. This may lead to additional spider veins and varicose veins, and in some cases can lead to swelling and venous ulcers at the lower calf and ankle. Only a trained vein specialist can effectively evaluate your spider veins or varicose veins.