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- Asthma, eosinophilia, and systemic vasculitis are the hallmarks of eosinophilic granulomatosis with polyangiitis (EGPA; Churg-Strauss syndrome).
- Classic clinical features include the following:
- Allergic rhinitis and nasal polyposis.
- Reactive airway disease.
- Peripheral eosinophilia (10–60% of all circulating leukocytes).
- Fleeting pulmonary infiltrates and occasional alveolar hemorrhage.
- Vasculitic neuropathy.
- Congestive heart failure.
- Approximately 50% of patients with EGPA have antineutrophil cytoplasmic antibodies (ANCAs), usually with a specificity for myeloperoxidase (MPO).
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In 1951, Churg and Strauss reported a series of 13 patients with “periarteritis nodosa” (see Chapter 35) who demonstrated severe asthma and an unusual constellation of other symptoms: “fever…hypereosinophilia, symptoms of cardiac failure, renal damage, and peripheral neuropathy, resulting from vascular embarrassment….” The investigators termed this new disease “allergic angiitis and allergic granulomatosis,” and specified three histologic criteria for the diagnosis: (1) the presence of necrotizing vasculitis, (2) tissue infiltration by eosinophils, and (3) extravascular granuloma.
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In 1990, an American College of Rheumatology panel liberalized the criteria for the classification of this disease, dropping the requirements for histopathologically proven vasculitis and granuloma (Table 34–1). The Chapel Hill Consensus Conference on nomenclature of the vasculitides subsequently defined the Churg-Strauss syndrome as a disorder characterized by eosinophil-rich, granulomatous inflammation of the respiratory tract and necrotizing vasculitis of small- to medium-sized vessels, associated with asthma and eosinophilia. In 2012, the Revised Chapel Hill Consensus Conference Nomenclature of Vasculitides recommended the term “eosinophilic granulomatosis with polyangiitis (EGPA)” for this disease. The purpose for this recommendation was twofold: (1) to emphasize certain cardinal features of the condition, and (2) for consistency with the names preferred for two related disorders, granulomatosis with polyangiitis (formerly Wegener granulomatosis)(see Chapter 32) and microscopic polyangiitis (see Chapter 33).
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