Thread veins are tiny veins in the skin that are invisible. They are found on cheeks, legs, nose, etc. However too much exposure to sun, pregnancy, estrogen treatment, and other reasons may result in these tiny veins expanding and showing through the skin. When they expand, they may look purplish and give the skin an unhealthy and embarrassing appearance. Thread veins can also develop due to a skin condition known as Rosacea or from the continued use of steroid creams. Thread veins are also known as spider or capillary veins.
 
Some simple ways of treating spider veins are covering them up with a concealer or using an artificial suntan preparation.  Or you can have laser treatment to cure thread veins.

Laser treatment is a fairly simple procedure in which a light beam is pulsed on the veins to seal them off and causing them to dissolve. There are various lasers and light sources used to treat spider veins.

Make sure to find a licensed, board certified doctor when considering any cosmetic treatment. And before undergoing any procedure, be sure to ask detailed questions to make sure that you understand all the risks and benefits associated with the procedure.