Churg–Strauss syndrome (CSS) is a rare systemic vasculitis of the small and medium sized blood vessels. The triad of asthma, sinusitis and hypereosinophilia is characteristic of CSS. However, it can affect any organ system with predominance for the skin, respiratory, neurological, gastrointestinal and cardiovascular systems. The natural history of the condition has been described in three phases: prodromal, eosinophilic and vasculitic. Depending on the organ system affected and stage of the disease, the presentation of CSS can be varied and the diagnosis can be challenging. The most frequently used criteria for diagnosing CSS are those developed by the American College of Rheumatology in 1990. Such classification criteria can assist in making the diagnosis of CSS and differentiating the condition from other diseases that cause pulmonary infiltrates with eosinophilia including allergic bronchopulmonary aspergillosis, acute and chronic eosinophilic pneumonia, idiopathic hypereosinophilic syndrome, certain parasitic infections and drug reactions. We present a case that is characterized by hypereosinophilia, vasculitis involving mainly the pulmonary and nervous systems, with a history of allergic rhinitis and sinusitis. Early diagnosis is crucial so that systemic glucocorticoids (the mainstay of treatment) can be commenced and can help to prevent organ damage and mortality.

Keywords: Churg–Strauss syndrome, Eosinophilic granulomatosis polyangiitis, Pulmonary infiltrates