Nasal Airway Resistance and Latent Lower Airway Involvement in Allergic Rhinitis

Allergic rhinitis (AR) and asthma are closely linked atopic conditions, often termed as one airway one disease. Nasal airflow obstruction is a cardinal symptom of AR and objective assessment of resistance to nasal airflow in rhinitis can be measured by active anterior rhinomanometry. This study was aimed at correlating the degree of resistance to nasal airflow (NAR) with the clinical severity of allergic rhinitis. In addition, it aimed at determining the proportion of patients with latent lower airway involvement in AR and studying the impact of ARIA severity grade and NAR on this value.

A prospective prevalence study was conducted wherein 32 patients diagnosed with allergic rhinitis underwent determination of nasal airway resistance by active anterior rhinomanometry and lung function evaluation by spirometry. If spirometry was normal; histamine challenge test was performed to check for bronchial hyper-reactivity.

94% of patients with moderate- severe allergic rhinitis had significantly elevated nasal airway resistance compared to 56% of patients with mild rhinitis. (p=0.014). 71.9% of patients with allergic rhinitis but no symptoms of asthma had bronchial hyper-reactivity with a positive histamine challenge or airflow obstruction on lung functions. 87.5% patients with significantly elevated nasal airway resistance compared to 25% with lower values had lower airway involvement. (p=0.001). 94% of patients with moderate - severe rhinitis and 83% of patients with persistent rhinitis compared to 50% patients with mild and 44% with intermittent symptoms had lower airways involved. (p<0.05).

Significantly greater proportion of patients with moderate-severe and persistent allergic rhinitis had elevated nasal airway resistance values. 72% patients with allergic rhinitis had lower airway involvement despite having no symptoms of asthma, prevalence being greater in patients with severe and persistent disease. Proportion of patients with lower airway hyper-responsiveness is significantly higher among patients with raised nasal airway resistance as determined by rhinomanometry. This study thus concludes that measurement of nasal airway resistance determined by active anterior rhinomanometry is a good objective tool to measure severity of nasal obstruction in allergic rhinitis with good correlation with the ARIA clinical severity grade .It may also be a promising tool to identify allergic rhinitis patients who are at a higher risk of having latent lower airway involvement.