How useful is the presence of petechiae in distinguishing non-accidental from accidental injury?

The presence of petechiae in a child with an unexplained injury should raise the practitioner's concern about possible non-accidental injury and prompt further inquiry. Absence of petechiae is not helpful in excluding non-accidental injury. In non-accidental injury, petechiae are most likely to be found on the head and neck, and usually in association with other bruises. Among the 28 cases in which petechiae were associated with non-accidental injury in our study, patterning of petechiae was noted in a quarter. Patterning was not noted in accidental injury cases with petechiae but the numbers were too small for firm practice conclusions to be drawn.