Varicose veins that are small are referred to as spider veins. Spider veins occur in the capillaries, and they can appear as spider web patterns on the skin. The lines appear blue and are about as thick as a large hair. The spider veins can also appear as disconnected lines or in star-burst patterns. Veins are blood vessels, and capillaries are simply veins that are small. The heart pumps blood out from larger veins called arteries. The blood travels through the lungs to pick up oxygen and then throughout the body into capillaries, where body tissue picks up the oxygen it needs. The blood returns to the heart to repeat the process. Veins and capillaries have valves in order to keep the blood flowing in one direction. When these valves fail, blood can pool and cause veins to bulge, resulting in spider veins.
Puberty
Advancing age is one of the main risk factors for the onset of varicose veins, but puberty can also be a factor. Puberty causes shifts in hormone levels. Some hormones can affect the strength of the walls of veins. Weakened vein walls can lead to spider veins.
Weight
Obesity can lead to increased blood pressure, which increases the pressure in the veins. This can lead to the valves in veins to not function properly and cause varicose veins and spider veins.
Pregnancy
Young women who are pregnant also experience an increase in blood pressure and spider veins. With pregnancy, changes in hormone levels may also play a role. The changes in hormone levels that occur during a pregnancy can make vein walls relaxed, increasing the risk for spider veins to occur.
Lack of Movement
Standing or sitting in one position for long periods of time, can cause spider veins. The lack of movement forces veins to work harder and can cause blood to pool.
Hormonal Changes
Changes in hormone levels, including hormone replacement therapy and birth control pills, can cause spider veins.
