What Causes Spider Veins?

Vein Surgery

Vein surgery can sometimes cause spider veins, if the surgery leads to the valves in the patient's veins becoming damaged or malfunctioning. Valves weakened by surgery may not be able to keep blood flowing toward the heart because they stay open instead of closing. Weak valves might also develop if the walls of the veins are weak, which can also be caused by vein surgery. Weakened vein walls aren't as elastic as they normally are, and instead resemble a rubber band that's stretched too tightly. The valve flaps separate when the vein stretches and widens, preventing the healthy flow of blood. Separated valves, which might be caused by surgery, aren't able to hold back the blood from flowing backward. The backflow causes more stretching and twisting, which then causes the veins to become twisted and large. Spider veins are often treated with vein surgery, but this surgery can also cause more to develop.

Keep reading to uncover information on more causes of spider veins now.

Skin Injuries

Some individuals have reported they developed spider veins after an injury or trauma to their skin. Skin injuries and leg injuries might damage the valves that control blood flow. Some individuals might only experience spider veins in the injured area. For others, the backflow of blood might lead other valves to become weaker, which in turn will cause spider veins to develop in other places in the legs or abdomen. Injuries might also make existing spider veins worse, though this isn't always the case. There are several different types of skin injury, and not every injury that might cause spider veins is severe. Tears, gashes, lacerations, and cuts are skin injuries that move through the skin to the fatty tissue underneath. Floor burns, scratches, abrasions, and scrapes are surface wounds and don't go all the way through the skin. Bruises are bleeding under the skin caused by damage to blood vessels. Surface abrasions are unlikely to contribute to spider veins unless they cause very unusual damage to blood vessel valves. Meanwhile, cuts and gashes deep enough to bleed are more likely to cause valve damage.