Thread veins refer to small blood vessels that run across to the skin surface. They look like fine red or at times they might look purple, wiggly veins. They are also known as spider veins or broken veins despite that they are also not broken, just slightly bigger.
In most cases thread veins tend to develop as a person ages and the blood vessels and skin become elastic. It is also believed that hormonal changes that occur during pregnancy and during menopause can also contribute to their occurrence. This is one of the major reasons why women are more prone to this issue.