Haemoptysis: is it really from the lungs? The well child who spits out blood.

Blood appearing in a previously well child's mouth may have many sources, and it should not be assumed to be haemoptysis, that is, coming from the respiratory tract below the larynx. In addition to the lungs and lower airways, consider also the upper airways, the mouth, gastrointestinal tract and cardiovascular conditions. This article discusses the differential diagnosis and appropriate investigations.