Thread veins tend to branch out and give a spidery sort of pattern hence their common name (spider veins). Thread veins are harmless.
Thread veins tend to be more visibly ageing than lines or wrinkles, which makes many people take action to have them removed. Thread veins are very common, especially in people in their 40s, 50s and 60s. Pretty much all women will experience thread veins at some point in their lifetime and they are usually associated with underlying vein problems.