Pulmonary manifestations of systemic vasculitis in childhood.

The systemic vasculitides are a heterogenous group of rare conditions with an incompletely understood aetiology. Any of the systemic vasculitides may cause respiratory disease, but some conditions are more likely to affect the pulmonary system, often through pulmonary infarction and diffuse alveolar haemorrhage. These conditions are often difficult to diagnose due to their rarity and significant clinical overlap with common respiratory conditions. Prompt diagnosis and management can significantly reduce morbidity and mortality.