ACR Criteria for the Classification of Churg-Strauss Syndrome (CSS)

American College of Rheumatology 1990 criteria for the classification of Churg-Strauss syndrome (CSS). Classified as CSS if at least four of six criteria are present

1. Asthma: History of wheezing or diffuse high-pitched expiratory rhonchi.
2. Eosinophilia: Eosinophilia >10% on differential white blood cell count.
3. Mono- or polyneuropathy: Development of mononeuropathy, multiple mononeuropathies, or polyneuropathy (glove/ stocking distribution) attributable to systemic vasculitis.
4. Pulmonary infiltrates, non-fixed: Migratory or transitory pulmonary infiltrates (not including fixed infiltrates) attributable to vasculitis.
5. Paranasal sinus abnormality: History of acute or chronic paranasal sinus pain or tenderness or radiographic opacification of the paranasal sinuses.
6. Extravascular eosinophils: Biopsy including artery, arteriole or venule showing accumulations of eosinophils in extravascular areas.