Although unknown many believe it is over stimulation of blood vessels, which dilate or enlarge blood vessels.
Intense pulsed light and laser systems release precisely controlled strong pulses of filtered light that are absorbed by the blood vessel, heating it to a point where it is destroyed. Following treatment the vessels quickly clear and are re-absorbed by the body, leaving little or no trace of the original lesion.
Redness and a warm sensation are normal after treatment. A cool pack may be applied to ease these symptoms. The vessels should fade quickly, and some disappear immediately.