Increased cys-leukotrienes in exhaled breath condensate and decrease of PNIF after intranasal allergen challenge support the recognition of allergic rhinitis in children.

Exhaled breath condensate (EBC) contains various mediators of inflammation. Since their concentrations correlate with severity of inflammatory response, EBC assessment allows non-invasive detection of various respiratory tract diseases and enables monitoring of their progression or treatment effectiveness. In this study, authors evaluate the usefulness of cysteinyl leukotrienes (cysLT) measurement in EBC, as non-invasive diagnostic markers of allergic rhinitis in children. It has been found that the assessment of cysLT in EBC, when performed out of the natural allergen exposure, can discriminate between healthy and allergic rhinitis individuals, with sensitivity 87.8% and specificity 76.4%, at the threshold level 39.05 pg/ml. The change of peak nasal inspiratory flow (ΔPNIF), measured before and after intranasal allergen challenge allowed recognition of healthy/allergic rhinitis-suffering individuals with sensitivity 76.8% and specificity 78.6%, at the threshold level of -3.2 l/min. When ΔPNIF assessment was combined with the measurement of cysLT in EBC, the sensitivity of such diagnostic approach reached 100% and its specificity increased up to 84.6%. The proposed algorithm was found to sufficiently discriminate between allergic rhinitis-suffering and healthy children, however, its clinical usefulness especially in young children requires further studies.