What could be caulsing my random nose bleeds?

Nose bleeds. Nose bleed reasons: nasal congestion or nasal dryness, ^ blood pressure, excessive use of decongestants, being at ^ altitude, trauma to nose, nose picking, or blowing the nose hard. Bacterial & viral infections can ^ risk as well as bleeding disorders. Recurrent nose bleeds may be due to broken vessel in the nose. Alcohol / Cocaine abuse can cause nose bleeds, as can tumors.
Many causes. Nose bleeding can be caused by simple things like dry air, trauma, medications. But also more worrisome things like bleeding disorders, uncontrolled hypertension or non-healing nasal lesions/ulcers and possibly cancer. I recommend you visit your physician to determine the etiology/cause.

Related Questions

Someone I know is having a nose bleed for about 20 minutes and he gets these nose bleeds randomly for about 4 days now & can he do anything for this?

He needs testing. Unless there is obvious trauma to the nose, he needs to have blood work, starting with his primary care doctor, to include a cbc, PTT and inr .. Read more...
Blood work. It could be the result of a cold or infection or something more. His doc can do some blood work to see if your friend has difficulty clotting and help if needed. That help could be medicine or diet modification. Read more...