Idiopathic eosinophilic pneumonia

Idiopathic eosinophilic pneumonia refers to a group of rare lung diseases characterized by an abnormal accumulation of eosinophils (a type of white blood cell) in the lung tissue and air spaces, without an identifiable cause. This category encompasses two main forms: acute eosinophilic pneumonia (AEP) and chronic eosinophilic pneumonia (CEP), also known as idiopathic chronic eosinophilic pneumonia or Carrington disease. The condition primarily affects the respiratory system, leading to inflammation and damage of the lung parenchyma. When no underlying cause such as parasitic infection, drug reaction, or allergic bronchopulmonary aspergillosis can be identified, the condition is classified as idiopathic. Acute eosinophilic pneumonia typically presents with rapid onset of fever, cough, shortness of breath, and can progress to acute respiratory failure requiring mechanical ventilation. It may occur in previously healthy individuals and has been associated with new-onset smoking or environmental exposures, though by definition the idiopathic form has no identifiable trigger. Chronic eosinophilic pneumonia develops more gradually, with symptoms including progressive cough, dyspnea, fever, weight loss, night sweats, and malaise, often over weeks to months. Peripheral blood eosinophilia is common in the chronic form but may be absent in the acute form. Chest imaging typically shows bilateral peripheral or migratory pulmonary infiltrates, classically described as the "photographic negative of pulmonary edema" in chronic eosinophilic pneumonia. Treatment for both forms centers on systemic corticosteroids, which typically produce a dramatic and rapid clinical response. Acute eosinophilic pneumonia usually resolves completely with corticosteroid therapy and rarely recurs. Chronic eosinophilic pneumonia also responds well to corticosteroids, but relapses are common (occurring in over 50% of patients), often necessitating prolonged low-dose maintenance therapy for months to years. In refractory or relapsing cases, steroid-sparing agents such as mepolizumab (an anti-IL-5 monoclonal antibody) have been explored. The prognosis is generally favorable with appropriate treatment, though chronic eosinophilic pneumonia may require long-term management to prevent recurrence.

Common questions about Idiopathic eosinophilic pneumonia