Localized vasculitis restricted to a specific anatomic site or organ is often histologically indistinguishable from more severe, systemic forms of vasculitis. By definition, localized vasculitis involves blood vessels within a confined vascular distribution or single organ without clinical evidence of generalized inflammation. Important factors that determine treatment and prognosis, in what appears initially to be a localized process, include histopathologic type, organ site, and the presence of systemic inflammatory markers and symptoms. The major issue is whether single organ vasculitis is actually an isolated form of the disease in which case surgical excision is curative, or whether the single organ involvement is simply a precursor of more threatening systemic vasculitis. The Birmingham Vasculitis Activity Score is a valuable tool to identify those patients with concurrent systemic involvement. The physician's recognition of a localized versus systemic vasculitic process is important in terms of making the correct diagnosis, prescribing treatment, and arranging appropriate clinical follow-up.