Sara
At 6, it's unlikely that high blood pressure is causing these. More than likely, he is dehydrated and the tissues are traumatized. Using a vitamin 'E' oil, applied to the inside of the nostrils on a regular basis will help, but may not resolve the issue. Try a humidifier in the childs room at night. I hope you have had an ear nose & throat Doc evaluate him. They often times will use a silver nitrate application to 'cauterize' the vessel that is causing the bleeding. This is painful and can hopefully be avoided. Encourage the child to drink more water. Sara