Face and leg thread vein treatments sclerotherapy thread veins broken veins or telangiectasia are the small red or blue veins which can appear anywhere on the body but are most common on the face and leg thread vein thread veins are caused by a variety of factors including exposure to ultra violet light wind and extremes of temperature steroid creams and the hormonal changes that occur during pregnancy can also induce thread veins some individuals are genetically more prone to develop t