Eosinophilia in patients presenting with pulmonary infiltrates and fever

A variety of infectious and noninfectious pulmonary disorders can present with pulmonary infiltrates with peripheral eosinophilia. Specific therapies are available for many of the pulmonary eosinophilic syndromes and failure to treat these syndromes can result in the development of irreversible lung disease. Clearly, an infectious etiology needs to be excluded before initiating glucocorticoid therapy for a presumed hypersensitivity reaction. However, the distinction between infectious and noninfectious processes can be difficult to make on clinical grounds alone. For these reasons, the evaluation of a patient presenting with this problem provides an interesting challenge to the physician.