Their medical name is telangiectasias (pronounced tee-lan-jek-tay-zhuhs). They are tiny veins on the surface of the skin, and may be thinner than a hair or nearly as wide as a spaghetti noodle. They vary in prominence from pink, to red, to purple. They can be single and isolated, or occur in clusters that can look like a large bruise. They are actually dilated veins of the skin that are normally too small to see. They may enlarge for different reasons.
Many of the factors that aggravate the tendency to form spider veins cannot be reasonably eliminated. Most people with spider veins have inherited a predisposition to develop them, and, of course, your genetics won’t change. Gravity affects the development of abnormal veins, and that is not something we can change either. Being female carries a higher risk to develop abnormal veins. Estrogens seem to play a role in the appearance of many spider veins, and these can occur not only on the legs, but also the face, chest, and abdomen. Sometimes spider veins occur after an injury to any area, like being hit by a ball or having surgery, and probably represent some disruption of the normal veins in the area from the injury.
Most spider veins can be seen to have associated reticular, or feeding, veins. These are blue veins just beneath the skin that are about the width of a ribbon that may or may not be a cosmetic concern. However, when associated with spider veins that are to be treated, the reticular veins must also be treated to get optimal results. Spider veins may also occur as a manifestation of abnormalities of even larger veins beneath the skin. They often occur in this setting along with varicose veins or prominent, or bulging, reticular veins. Spider veins may also occur with abnormalities in the major deep and superficial leg veins. It is very important to recognize the signs of associated vein disease, as leaving it untreated will result in a poor outcome when the spider veins are treated. Failure to treat associated vein disease is the most common reason for poor results in patients we see who have had treatment elsewhere.