I used to suffer really badly with nosebleeds as a child, no explanations were given to my parents other than 'it's just one of those things' that was over 20 years ago (God, I feel old) but I grew out of them, if you're really concerned ask your GP!
I dont know but my daughter gets them really bad. Shes had them since she was two and they are getting worse rather than better. Quaterising doesnt help either. She has been hospitalised before now with them. She's had blood tests to see if she has a blood clotting disorder but she doesn't so i'm hoping that they will go eventually. In them time she's had them (she's now 12) the longest she has gone without a nosebleed is 9 months. she can have as many as 10 in one week
i agree my little girl came down from her room with blood all over after i had a panic attack realised it was her nose! and yes at 4 yrs old she agreed she had picked it !!