The vasculitides are a range of disorders in which the primary pathological process is inflammation of blood vessels.
The vasculitides are rare and often present with non-specific symptoms and signs; as a result the diagnosis may be delayed. Advances in the treatment of the vasculitides have made the early diagnosis of these syndromes essential because early interventions prevent complications and improve prognosis.
The vasculitides have been reclassified according to the size of the vessels affected and the role of various auto-antibodies in diagnosis and pathogenesis.
Many other diseases cause a vasculitis as a secondary feature, these are covered separately.