Spider veins or varicose veins are gnarled, enlarged veins. Veins most commonly affected are those in your legs and feet. That’s because standing and walking upright increases the pressure in the veins of your lower body. Varicose veins can cause aching pain and discomfort. Sometimes varicose veins lead to more-serious problems. Varicose veins may also signal a higher risk of other circulatory problems.