The underlying cause of asthma is inflammation of the airways. Asthma is technically defined as a chronic inflammatory process that leads to air-flow restriction and increased responsiveness to asthma triggers. Yet the diagnosis and monitoring of asthma has traditionally focused on methods that only evaluate symptoms and lung function. These do not truly assess the underlying cause, and do not reflect the way the patient self-assesses his or her asthma.
FE
NO measurement enables routine and immediate assessment of the underlying inflammation and as a result can help guide the most appropriate treatment options.
Understanding the type of inflammation that causes asthma symptoms is important in deciding the right course of therapy. Until recently, most treatment and prevention strategies were based on a “one size fits all” approach (Douwes 2002) that assumed all asthma inflammation was identical.[Douwes 2002] It is now generally acknowledged that allergen-triggered asthma is associated with eosinophilic inflammation and it is this type of inflammation that is associated with elevated nitric oxide (NO) production. Various studies have also shown that eosinophilic inflammation is the type that responds best to ICS treatment [Brigthling 2000, Smith 2005] .