Persistent lower respiratory disease in children.

Recurrent or persistent lower respiratory disease in children may present in various ways. The differential diagnosis includes reactive airways disease (asthma), prolonged viral pneumonia (in the young infant) and foreign body aspiration-the most common causes of persistent respiratory symptoms. The differential diagnosis also includes a long list of rare conditions. Because of the many diagnostic possibilities, the evaluation of a child with persistent lower respiratory disease should be carried out in a systematic, stepwise fashion.