LAUSR

Background Acute eosinophilic pneumonia (AEP) is an uncommon disease, often indistinguishable from ARDS or community‐acquired pneumonia at initial presentation. AEP can be idiopathic, but identifiable causes include medications and inhalational exposures, including cigarette smoke. Methods Using a computer‐assisted search, we retrospectively identified and reviewed the medical records of all patients diagnosed with AEP between January 1, 1998, and June 30, 2016, at our institution. Demographic and clinical data were extracted, including exposures (occupational, environmental, recreational, pharmacologic, and smoking), laboratory and radiologic findings, treatments, hospitalization (including ICU stay), and subsequent clinical course. Results Among 36 consecutive patients with AEP, 11 were smoking‐related cases, six were medication‐related cases and 19 were idiopathic. Smoking‐related AEP included six first‐time smokers and five ex‐smokers who had resumed smoking after a period of abstinence. Patients with smoking‐related AEP were younger compared with both medication‐related and idiopathic AEP cases (median age: 22 vs 47.5 vs 55 years, respectively; P = .004). Patients with smoking‐related AEP were less likely to be associated with peripheral eosinophilia at presentation (36% vs 50% vs 58%; P = .52) but more likely to be hospitalized (100% vs 50% vs 63%; P = .039), including a longer ICU stay, compared with medication‐related and idiopathic cases. Conclusions AEP is associated with a good prognosis when recognized and treated promptly. Compared with medication‐related and idiopathic AEP, smoking‐related AEP was less likely to be associated with peripheral eosinophilia at presentation but was characterized by more severe disease manifestations.