By far the most common cause of nosebleeds--"epistais" is the health care word for it-is trauma, meaning an injury or wound.  This could mean a fist or a fingernail; in fact, the most common cause of nosebleeds in children is chronic nose-picking.

Most nosebleeds are due to simple injury, they can sometimes signal important health problems.  One of the major causes of nosebleeds among elderly patients is high blood pressure.  When the pressure goes up something can give, like blood vessels inside the nose.  Nosebleeds can signal inherent bleeding problems.  If a patient's blood has trouble clotting-for whatever reason--then the nose knows it.  When a blood "dyscrasia" like this is responsible for a nosebleed it can take time, effort or sometimes even hospitalization to stem the bleed.

There are still other causes for nosebleeds, such as tumors, including malignant ones; and, some people are born with abnormal blood vessels that tend to bleed.

Many, if not most normal children have an occasional, easily controlled nosebleed.  But recurrent nosebleeds in a child or new and recurrent nosebleeds in an adult should looked into.  For a copy of this script, access our web site, speakingofhealth.com.  Speaking of Health for CBS News.