To investigate the clinical characteristics of children with chronic cough and to evaluate the predictive value of fractional exhaled nitric oxide (FeNO), peripheral blood eosinophil (EOS) count, and total immunoglobulin E (IgE) for airway hyperresponsiveness (AHR). This retrospective, cross-sectional study included 142 children with chronic cough who underwent bronchial provocation testing (BPT) at the Children’s Hospital of Hebei Province between September 2024 and August 2025. Based on BPT results, participants were divided into an AHR-positive group ( n = 119) and an AHR-negative group ( n = 23). We compared clinical features, pulmonary function parameters, FeNO levels, EOS counts, and total IgE levels between the two groups. Receiver operating characteristic (ROC) curves were generated to assess the predictive performance of FeNO, EOS, and IgE for AHR, including pairwise and triple combinations. The AHR-positive group exhibited a significantly higher prevalence of nocturnal cough (68.9% vs. 26.1%, P < 0.001), eczema/urticaria (68.1% vs. 34.8%, P = 0.004), allergic rhinitis (66.4% vs. 34.8%, P = 0.006), and allergic conjunctivitis (68.1% vs. 21.7%, P < 0.001) compared to the AHR-negative group. Patients with AHR had significantly lower small airway function parameters, including FEF75%pred (Median: 64.5% vs. 74.1%, P = 0.038) and FEF25%-75%pred (Median: 66.6% vs. 86.5%, P < 0.001). Furthermore, FeNO (Median: 27.3 vs. 19.0 ppb, P = 0.022), EOS count (Median: 0.35 vs. 0.19 × 10⁹/L, P = 0.045), and total IgE levels (Median: 262.1 vs. 121.1 IU/mL, P < 0.001) were all significantly elevated in the AHR-positive group. ROC analysis showed that total IgE had the best individual predictive value (AUC: 0.724), followed by FeNO (AUC: 0.651) and EOS (AUC: 0.632). A combined model incorporating all three biomarkers demonstrated superior predictive accuracy (AUC: 0.852). Significant negative correlations were observed between AHR severity and levels of FeNO and IgE. Children with chronic cough and AHR present distinct clinical and physiological profiles characterized by atopic comorbidities, small airway dysfunction, and elevated type 2 inflammatory biomarkers. The combined assessment of FeNO, EOS, and IgE offers significant clinical value as a non-invasive screening tool for predicting AHR in this population, potentially guiding risk stratification in settings where BPT is not readily accessible. Further external validation is required before routine clinical implementation.
Bian et al. (2026) studied this question.