Key Message
Wheezing and rattling are two distinct types of noisy breathing with different underlying pathological mechanisms, different treatment options and different long-term scenarios. However, rattling infants are often mislabelled as wheezing leading to overtreatment with bronchodilators and/or inhaled corticosteroids (ICS). ICS will not benefit the rattling infant, but can have adverse effects on linear growth potentially causing significant growth reduction. Currently there are no objective diagnostic tools to diagnose noisy breathing infants and the clinician can solely rely on auscultation, parent reports and physical examination. There is a need for non-invasive and objective techniques to achieve early differential diagnosis which is of high importance for a “precision medicine” approach to prevent under- and overtreatment. In the Non-invasive Noisy breathing Infant study showed that the analysis of exhaled volatile biomarkers could have potential as a clinical tool for detection and classification of rattling in infants. Future research should investigate the potential of exhaled breath to differentiate wheezing and rattling infants.