Epistaxis
"Epistaxis (or a nosebleed in plain English) is the relatively common occurrence of hemorrhage from the nose, usually noticed when the blood drains out through the nostrils."
(...)"Nosebleeds are due to the rupture of a blood vessel within the richly perfused nasal mucosa. Rupture may be spontaneous or initiated by trauma. Nosebleeds are reported in up to 60% of the population with peak incidences in those under the age of ten and over the age of 50 and appears to occur in males more than females. An increase in blood pressure (e.g. due to general hypertension) tends to increase the duration of spontaenous epistaxis."