ABSTRACT
Churg-Strauss syndrome (CSS) is a primary small vessel necrotizing vasculitis
characterized by asthma, lung infiltrates, extravascular necrotizing granulomas,
and hypereosinophilia (1). Churg and Strauss, in 1951, individualized CSS from
periarteritis nodosa on the basis of autopsy of 13 patients (1) and initially called
it allergic granulomatosis and angiitis. Asthma (usually severe and of late onset)
is a hallmark of CSS, present in almost all patients but other thoracic manifes-
tations may occur, including lung infiltrates in about 70%, pleural effusions, and,
more rarely, hilar lymphadenopathy and alveolar hemorrhage. CSS is one of the
antineutrophil cytoplasm autoantibody (ANCA)-associated vasculitides (AAV),
which also comprises microscopic polyangiitis (MPA) and Wegener’s gran-
ulomatosis. However, ANCAs are not always found in CSS patients. Two recent
studies described two CSS phenotypes, on the basis of ANCA status, suggesting
two distinct pathogenic mechanisms (2,3).
