Drug-induced eosinophilic lung disease.

For most patients who have suspected drug-induced eosinophilic lung disease, the history provides a presumptive diagnosis that can be confirmed by pulmonary findings and eosinophilia after cessation of the drug. As new drugs are developed and released for clinical use, many will result in eosinophilic lung disease in susceptible patients. Therefore, development of pulmonary abnormalities in conjunction with blood or lung eosinophilia after prescription ofa newly released medication should raise the possibility of drug-induced lung disease, even if that medication has not yet been reported to cause eosinophilic lung disease. In all patients, the diagnosis requires exclusion of other causes of eosinophilic lung disease by history, and, if necessary, laboratory testing or lung biopsy.