Causes of Spider Veins

Updated on: August 18, 2014

What are spider veins?

Spider veins are small veins which are located just below the skin surface. They are called spider veins because on close observation they resemble a dark center with fine radiating lines in a circular fashion. Other names by which spider veins are often known as include "star" veins or telangiectasias. Spider veins are common and most individuals (especially females) have one or multiple spider veins somewhere on their body. Spider veins are generally more common on the legs, especially around the thigh and ankle area. Even though they occur in all ethnic populations, they are most obvious in fair skinned individuals. Because of their prominent bluish color, they are considered a cosmetic nuisance by most females.

What Causes Spider Veins?

No one really knows why spider veins occur but the incidence is definitely increased by the following factors:

Age: Spider veins are rarely seen in children and young teenagers. Most individuals develop spider veins after the 3rd decade of life. As people get older, the spider veins do increase.

Elderly individuals have very friable skin and easily develop bruising and spider veins.

Genetics: There is a higher incidence of spider veins in siblings if any one of the parents or other siblings has spider veins. The pattern of inheritance is not exactly known or understood. Spider veins have not been associated with any known medical disorder.

Pregnancy: Spider veins are very common during pregnancy. This is believed to be due to the increase in body weight and retention of fluids. The increased fluid retention leads to engorgement of the veins and which causes pressure on the smaller branch veins. These small branch veins with thin walls become distended and frequently rupture. Another factor related to increased incidence of spider veins during pregnancy is the female sex hormone- estrogen. Estrogen is known to soften the vein wall and the valves which control blood flow. The stretching of the veins is believed to cause an increase in blood engorgement- which eventually leads to spider vein formation.

During the last trimester of pregnancy, the fetus may put pressure on the leg veins by compressing the lower pelvis. For this reason it is highly recommended that pregnant females lie down on their left side to prevent the fetus from lying on top of the leg veins. Multiple pregnancies are often associated with numerous spider veins which rarely resolve.

Prolonged standing: Individuals who have occupations that involve prolonged standing are more prone to development of spider veins. This is believed to be due to the increased amount of venous pressure in the legs. The muscles of the leg do not become active and this further results in the pooling of blood in the leg. The increased pressure in the large veins is then transmitted to the smaller veins on the skin, which causes them to rupture and present as spider veins.

Prolonged sitting: Individuals who sit for prolonged times are also prone to spider veins. The sitting causes inactivity of the leg muscles and leads to pooling of blood in the leg; this also causes increased venous pressure. As soon as you start to walk the blood starts to circulate and the pressure drops.

Trauma: There are numerous small fine veins underneath the skin. Any type of trauma can cause these veins to rupture and present like spider veins.

Sun: Spider veins on the face are not related to increased venous pressure. Excessive sun exposure has been associated with spider veins on the face.

Tight clothing: Wearing tight clothes, girdles or underpants with firm elastic bands can also lead to spider veins. The tight clothing limits the flow of blood and leads to increase venous pressure. The increased venous pressure in the groins and pelvis is then transmitted to the legs- which eventually leads to the formation of spider veins.


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