The correlation of exhaled nitric oxide, atopy, and severity of allergic rhinitis in taiwanese children with moderate persistent asthma

Background: Allergic rhinitis (AR) is characterized by eosinophilic infiltration and immunoglobulin E (IgE)-mediated reaction after exposure to an allergen. Its severity may be correlated to fractional exhaled nitric oxide (FeNO). This study aimed to evaluate the correlation of FeNO and various parameters with severity of AR in Taiwanese children with moderate persistent asthma. Materials and Methods: The study enrolled 103 children aged 5–18 years with AR and moderate persistent asthma from the Outpatient Department, Mackay Memorial Hospital, Taipei. Based on Total Nasal Symptom Score (TNSS), the patients were divided into high-score group (TNSS ≥5) and low-score group (TNSS <5). Both groups were assessed and compared by FeNO, blood eosinophil percentage, serum total IgE level, specific IgE levels to 8 allergens, and pulmonary function tests. Results: The low-score group showed significantly lower FeNO (18.57 ± 14.47 vs. 26.83 ± 17.84 ppb; P < 0.05), lower blood eosinophil percentage (3.08 ± 3.43 vs. 4.53 ± 3.37%; P < 0.05), lower level of serum total IgE (232.64 ± 438.88 vs. 510.63 ± 732.64 IU/mL; P < 0.05), and lower specific IgE to Dermatophagoides pteronyssinus (Der p), Dermatophagoides farinae (Der f), and dog (1.80 ± 2.35 vs. 3.66 ± 2.23, P < 0.05; 1.78 ± 2.36 vs. 3.56 ± 2.31, P < 0.05; and 0.00 ± 0.00 vs. 0.29 ± 0.81, P < 0.05). There are no significant differences between two groups about forced expiratory volume in 1 s (FEV1) (96.95 ± 13.39 vs. 97.85 ± 14.98% predicted; P = 0.75), FEV1/forced vital capacity percentage (89.00 ± 9.78 vs. 90.20 ± 5.85%; P = 0.47), and forced expiratory flow 25%–75% (55.16 ± 18.48 vs. 56.75 ± 20.15% predicted; P = 0.68). Conclusions: Taiwanese children with moderate persistent asthma with more severe symptoms of AR are significantly associated with higher levels of FeNO, total IgE, specific IgE to Der p, Der f, and dog, and higher blood eosinophil percentage.