What Causes Persistent Severe Nose Bleeds?

Hi Dr. Rynne,      My girlfriend Jen has been getting nose bleeds pretty persistently over the last four months. She just had an episode 20 minutes ago and it lasted for a relatively long time (5-10minutes) with excessive bleeding out of one nostril. There were large thick clots that came out, also. This last time was probably the worst we have seen.      Her PCP referred her to an ear, nose, and throat doctor and recommended that she may need her nose to be cauterized. Have you heard of such nose bleeding problems from patients who have nose piercings? The nostril that keeps bleeding has a piercing in it, and she at one time had her septum pierced, but no longer does. Thank you for your advice.