Background and aim FeNO (fractional exhaled NO) is an useful tool to assess asthma control, being correlated with eosinophilic inflammation of the respiratory tract. Nevertheless FeNO value varies according to asthma control status in just one subgroup of patients.

The aim of this study is to determine if atopy represent a feature that define the subgroup of patients for which FeNO is an appropriate tool for disease control assessment.

Method We have conducted a retrospective study including 47 patients diagnosed with bronchial asthma in our clinic between January–December 2013. From this group we have counted those patients who had during this period at least one testing with FeNO value >25 ppb (increased above normal limit and related to poorly controlled asthma); the variation of FeNO values is assigned to changes in asthma control status. Also from the same group we have spotted those patients who had atopy. Finally we have correlated the 2 sungroups: those with at least one FeNO value >25 ppb and those with atopy using Pearson Chi-Square test.

Results From 35 patient with atopy 18 patients had at least one testing with FeNO >25 ppb (51,4%); from 12 patients without atopy only one patient had at least one testing with FeNO >25 ppb (8,3%); Pearson Chi-Square test estimated that FeNO-atopy correlation is statistically significant (p = 0,013).

Conclusion FeNO value is correlated with atopy in asthmatic patients and atopy can be considered a feature that define the subgroup of asthmatic patients eligible to be monitored using FeNO.