Usefulness Analysis of Fraction of Exhaled Nitric Oxide for the Differential Diagnosis of Acute Cough.

Abstract

Measuring the fraction of exhaled nitric oxide (FeNO) is useful in the diagnosis of asthma and cough variant asthma. The aim of this study was to clarify the significance of measuring the FeNO in the differential diagnosis of acute cough. We analyzed 80 patients who visited the clinic with the chief complaint of acute cough having experienced an asthma-like episode from January 2014 to July 2015. Infectious cough alone was present in 21% of patients, while 30% had asthmatic cough alone and 49% had a combination of infectious and asthmatic cough. The values of FeNO in those with asthmatic cough (30.4±24.7 ppb) and asthmatic/infectious cough (33.2±17.4 ppb) were significantly higher than those with just infectious cough (13.7±3.2 ppb) (p=0.0089 and p<0.0001, respectively). FeNO measurement is useful for distinguishing asthmatic diseases, even in the differential diagnosis of acute cough.