Response

To the Editor:

We thank Drs John and Kontoyiannis for their interest in our approach to eosinophilia with pulmonary involvement.^1,2 As we noted in our review, pulmonary eosinophilia may be associated with diverse causes that have overlapping clinical, laboratory, and radiologic features. The differential diagnosis includes, but is not limited to, eosinophilic granulomatosis with polyangiitis and other vasculitides, hypereosinophilic syndromes, aspirin-exacerbated respiratory disease, eosinophilic pneumonias and bronchitis, allergic bronchopulmonary aspergillosis, a myriad of helminthic and non-helminthic infections, and drug-induced pulmonary eosinophilic syndromes.¹ John and Kontoyiannis² are correct to highlight daptomycin as an important cause of drug-induced eosinophilic pneumonia. Indeed, drug-induced pulmonary eosinophilic syndromes, with drug-induced hypersensitivity syndrome or drug reaction with eosinophilia and systemic symptoms being the more serious clinical presentations, have been linked to a variety of medications, including anticonvulsants, antibacterial sulfonamides, allopurinol, vancomycin, and minocycline.³ Our listing was not intended to be exhaustive, and we agree with their mention of a review of 196 case reports describing drug-induced eosinophilic pneumonia or drug-induced pulmonary infiltrates and eosinophilia, in which among 67 implicated medications, daptomycin and mesalamine were the leading causes of pulmonary infiltrates and eosinophilia , closely followed by minocycline and sulfasalazine.⁴ Drug-induced pulmonary eosinophilia varies in clinical presentation and may occur in conjunction with extrapulmonary manifestations. Close attention to medication and other exposures and their temporal association with eosinophilia and symptomatology may help ascertain an underlying cause and highlight the need for a systematic approach to the evaluation of eosinophilia with pulmonary findings.