Systemic Vasculitis, Primary and Secondary
Differential Diagnosis and Classification

Systemic vasculitides comprise a large group of inflammatory diseases with a suggestive or proven immunopathogenesis involving blood vessels of various sizes and affecting various organ systems. They are thus not one well defined entity but rather a collection of different diseases. Although systemic vasculitides are predominantly systemic diseases, some can initially remain localized for periods of time. They are classified according to involved vessel sizes which is associated with distinct clinical pathologies and prognoses. Their diagnosis requires a close cooperation of several specialties including clinicians, pathologists, laboratory physicians, and radiologists. Involved clinicians vary according to diseased organ systems and are preferentially dermatologists, pulmonologists, nephrologists, cardiologists, and neurologists.
Primary systemic vasculitis (PSV) is a disorder without previously identified conditioning disease entity, secondary systemic vasculitis (SSV) follows or accompanies given diseases such as infections, neoplasias or other autoimmune disorders such as connective tissue diseases.