<Li> Mediastinal compression by tumours (raised venous pressure) </Li> <Li> Thrombotic thrombocytopenic purpura </Li> <P> 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 appear to occur in males more than females . An increase in blood pressure (e.g. due to general hypertension) tends to increase the duration of spontaneous epistaxis . Anticoagulant medication and disorders of blood clotting can promote and prolong bleeding . Spontaneous epistaxis is more common in the elderly as the nasal mucosa (lining) becomes dry and thin and blood pressure tends to be higher . The elderly are also more prone to prolonged nose bleeds as their blood vessels are less able to constrict and control the bleeding . </P> <P> The vast majority of nose bleeds occur in the anterior (front) part of the nose from the nasal septum . This area is richly endowed with blood vessels (Kiesselbach's plexus). This region is also known as Little's area . Bleeding farther back in the nose is known as a posterior bleed and is usually due to bleeding from Woodruff's plexus, a venous plexus situated in the posterior part of inferior meatus . Posterior bleeds are often prolonged and difficult to control . They can be associated with bleeding from both nostrils and with a greater flow of blood into the mouth . </P>

Where does the blood from nose bleeds come from