Update in paediatric vasculitis.

Vasculitis refers to a heterogeneous group of disorders that are characterised by inflammatory destruction of blood vessels. Although simple to define, almost nothing about vasculitis is simple. From classification to diagnosis, and from pathogenesis to management, large gaps remain in our understanding. Despite extensive and ongoing research, the fundamental mechanisms underlying the initiation and continuation of systemic vasculitis remain poorly understood. Thus, vasculitis continues to provide tremendous challenges to both clinicians and investigators and remains a rich source of issues for discussion. This review concentrates on recent changes proposed for the classification of paediatric vasculitis and advances in the concepts of aetiopathogenesis. Availability of improved classification criteria for children should prompt planning for multicentre-controlled studies for the treatment of these rare but important diseases.