Exhaled nitric oxide in children with asthma and sinusitis

Exhaled nitric oxide (FENO) is a surrogate marker of eosinophilic airway inflammation. The measurement of this gas can be easily performed in children and the result is immediately available. Because of these characteristics, measurement of FENO is slowly becoming part of the routine clinical evaluation of an asthmatic patient. FENO measurement may have a role both in the diagnosis of asthma and as a guide in therapy algorithms. For example when FENO levels are persistently normal and the asthmatic child is asymptomatic, the steroid therapy may be decreased or even stopped. In patients with acute or chronic rhinosinusitis the levels of nasal nitric oxide (nNO) are significantly decreased, while they rise up after a course of antibiotics. The measurement of nasal NO has been proposed as a functional test to evaluate sinus ventilation. Nasal NO is significantly reduced also in primary ciliary dyskinesia and can be used as a screening tool to identify patients affected by this condition.