D1.97 - To FeNO or Not to FeNO: Is It a Practical Tool in Daily Management of Chronic Cough?

Chronic cough is a frequent cause of referral to allergy clinics. Type 2 airway inflammation may underlie a substantial proportion of cases, even without overt asthma. Fractional exhaled nitric oxide (FeNO) is a non-invasive biomarker, but its practical role in daily allergy practice remains under discussion.

A retrospective study included 32 patients (13 males, 5 children <12y) with chronic cough (>8 weeks). FeNO was measured before initiation of inhaled corticosteroids (ICS). Cough severity was evaluated using a Visual Analogue Scale (VAS) at baseline and after 4–8 weeks. Patients were stratified by FeNO: adults 0–20, 25–50, >50 ppb; children 0–20, 20–35, >35 ppb. Clinical response was defined as reduction in VAS score

In adults, patients with FeNO >50 ppb (n=4) had the largest mean VAS improvement (~38 points), whereas FeNO 25–50 ppb (n=7) and 0–20 ppb (n=16) had mean reductions of ~22 points. Among children, those with FeNO >35 ppb (n=2) had marked improvement (~35 points), while lower FeNO categories showed ~22-point reductions. High FeNO influenced clinical decision-making, identifying patients more likely to benefit from ICS therapy.

In this real-life setting, FeNO measurement is a practical and valuable tool for the evaluation of chronic cough in both adults and children. High FeNO identifies a type 2 inflammatory endotype associated with superior response to anti-inflammatory treatment, allowing more personalized management and potentially reducing unnecessary diagnostic procedures. These findings support the integration of FeNO measurement into routine allergy practice as a treatable trait biomarker for chronic cough.