[Epistaxis and circadian rhythm]

It is known that many physiological variables show a rhythmic variability along a time span, e.g.: day, week, month or year. It is possible that the temporal overlapping of a constellation of factors may act as favouring and/or triggering factors for the onset of several acute diseases. Among these, epistaxis shows a circadian variability too. Such pattern, characterised by a prevalent peak in the morning and a secondary one in the evening, strictly resembles that of arterial blood pressure. The lack of differences between the temporal pattern of hypertensive and normotensive subjects suggests that the physiological pattern of blood pressure, and not strictly a condition of hypertension, may play a favouring role in certain hours of the day, probably together other local factors.