Normal saline solution nasal-pharyngeal irrigation improves chronic cough associated with allergic rhinitis

Upper airway inflammation is one of the most commonly identified causes of chronic cough, although the underlying mechanism is not clear. This study compared normal saline solution nasal-pharyngeal irrigation (NSNPI) and fluticasone propionate nasal spray (FPNS) treatment for chronic cough associated with allergic rhinitis (AR).

Patients with suspected AR to house-dust mite were enrolled, and the symptom of cough was assessed by a cough symptom score and the Leicester Cough Questionnaire, and cough response to capsaicin was evaluated. AR was assessed by using the visual analog scale (VAS) and the Mini Juniper Rhinoconjunctivitis Quality of Life Questionnaire (MiniRQLQ). Mediators, including histamine, leukotriene C4, and prostaglandin D2, and the major basic protein from nasal lavage fluid (NLF) were examined. The patients were treated with NSNPI (the NSNPI group) or FPNS (the FPNS group) for 30 days, after which they were reassessed.

Forty-five of 50 patients completed this study. The scores of the cough symptom and the Leicester Cough Questionnaire, and the capsaicin cough threshold all improved statistically after NSNPI but did not change after FPNS. There were statistically significant changes in the evaluations of the MiniRQLQ and the mediators, including histamine and leukotriene C4, in the NLF in the NSNPI group. However, significant changes were found in the assessments of VAS, MiniRQLQ, and all above mediators including histamine, leukotriene C4, and prostaglandin D2, and the major basic protein in the NLF of the FPNS group. Furthermore, the assessments of VAS and all the mediators were reduced more in the FPNS group compared with those in the NSNPI group.

The patients with suspected AR to house-dust mite reported a better relief of the cough symptom after 30 days of treatment with NSNPI compared with that after nasal corticosteroid.