Update on eosinophilic lung diseases.

The eosinophilic lung diseases are a group of pulmonary disorders characterized by an increase in blood and/or lung eosinophils. These disorders can be primary pulmonary disorders or the secondary manifestation of other systemic or pulmonary conditions, infection, drug reaction, or malignancy. The approach to a patient with eosinophilic lung disease involves a thorough history and physical examination, review of exposures and appropriate testing, often including bronchoscopy or lung biopsy, to establish a specific etiology and determine therapy. Eosinophilic lung disease can be suspected based on either the finding of pulmonary disease with blood eosinophilia, pulmonary disease with bronchoalveolar lavage eosinophilia, or pulmonary disease with lung tissue eosinophilia on lung biopsy.