There are many causes for nosebleeds but the following are some of the major ones:-

• The inability of the blood to clot due to blood thinning medication such as aspirin or warfarin;
• Liver disease;
• Thinning of the membranes inside the nose causing the vessels to be very close to the surface;
• Rare causes -- abnormal blood vessels in the nose and nasal cancers;
• High Blood Pressure -- this may be a contributing factor but is almost never the only reason;
• Scratching the inside of the nose, especially if it is dry and crusty inside;

A question many people ask is whether they should go to the hospital.
Parents are especially concerned when a child has a nosebleed.
The following is the criteria for deciding on whether a visit to the hospital is necessary or not:-

• The nose is still bleeding significantly after 10 minutes of pressure on the nose;
• You are having repeated episodes;
• You are feeling dizzy or lightheaded and feeling like you are going to pass out;
• Rapid heart beat or trouble breathing;
• spitting up or vomiting blood;

I want to assure you that excessive blood loss from nosebleeds does not often occur.
However, this can happen so it is essential that you immediately do everything you can to stop the flow of blood.
If the nosebleed is originating from the posterior area, then the flow can be quite dramatic and it has to be stopped as soon as possible.
Those that originate from the anterior are less severe and also much easier to handle from the comfort of your own home.
Here are a few suggestions for stopping the bleed:

• pinch the nose for at least 10 minutes; do not let go at all during that period of time;
• put an icepack on the back of the neck;
• always lean forward otherwise the blood will trickle down the back of your throat;
• try to keep calm and not panic;
• you might want to roll some toilet paper up and pack the nostril and leave it in for a while;

It is a debatable question as to whether you should blow your nose when it is all over.
I was of the opinion that you should not..
..
that was until I had such a severe nosebleed that the ambulance was called.
The attendants periodically had me gently blow out the clot especially as I could hardly breathe because of the size of the clot.
This worked well for me, even though it took a few clots forming and subsequently getting rid of, before things subsided.
A posterior nosebleed can be quite dramatic and it can be very scary, especially if this is the first time you have experienced one.
I reiterate, please stay as calm as possible and just concentrate on stopping the bleeding.
It is a wise decision to make an appointment with an ear, nose and throat specialist if you are having recurring nosebleeds and especially if they are from the posterior area.