Acute eosinophilic pneumonia (AEP) is an uncommon disease, often indistinguishable from acute respiratory distress syndrome or community-acquired pneumonia at initial presentation. AEP can be idiopathic but identifiable causes include medications and inhalational exposures including cigarette smoke.
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. We extracted demographic and clinical data including exposures (occupational, environmental, recreational, pharmacologic and smoking), laboratory and radiological findings, treatments, hospitalization including intensive care unit stay, and subsequent clinical course.
Among 36 consecutive patients with AEP, 11 were smoking-related, 6 medication-related, and 19 idiopathic. Smoking-related AEP included 6 first-time smokers and 5 ex-smokers who had resumed smoking after a period of abstinence. Patients with smoking-related AEP were younger compared to both medication-related and idiopathic AEP (median age 22 vs. 47.5 vs. 55 years, respectively, p=0.004). Smoking-related AEP was less likely to be associated with peripheral eosinophilia at presentation (36% vs. 50% vs. 58%, p=0.52) but more likely to be hospitalized (100% vs. 50% vs. 63%, p=0.039), including a longer intensive care unit stay, when compared to medication-related and idiopathic cases.
AEP is associated with a good prognosis when recognized and treated promptly. In comparison to 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.