Mohammad Reza Pashaei - Department of internal medicine, Faculty of Medicine, Urmia University of Medical Sciences, Urmia-Iran

Aim: Asthma is one of the most common chronic diseases in adults characterized by variable airway obstruction. Asthma is diagnosed with symptoms such as wheezing and shortness of breath but sometimes manifested as a chronic cough that is difficult to diagnose and requires spirometry stimulation tests. The aim of this article was to investigate the relationship between methacholine test results and respiratory symptoms in patients with chronic unexplained cough . Material and Methods: This cross-sectional study included ۱۰۲ patients with chronic cough with normal basal spirometry. All patients underwent a methacholine challenge test and their airway irritabilities were assessed. Then, the relationship between methacholine test results and the type of associated clinical symptoms, underlying disease history, and demographic characteristics were investigated. Results: Of ۱۰۲ patients (۶۹ females and ۳۳ male) in this study, ۹۲ (۹۰.۲%) were non-smokers and ۱۰ (۹.۸%) were smokers. Rhinitis was also mentioned as a symptom of cough in ۴۸% of people with a positive test (P = ۰.۰۱). Postnasal discharge was reported as a symptom in ۶۰% of positive methacholine test persons, which was significant compared to the negative group (۳۶.۴%) (P = ۰.۰۳). Most people who tested positive were housewives (۷۶%). Of ۱۰۲ patients, ۲۵ (۲۴.۵%) had positive test results for methacholine (۸% male and ۹۲% female).Conclusion: According to the results of the present study, the presence of airway hypersensitivity, postnasal discharge, allergic rhinitis, , female gender, and being housewife were strongly associated with a positive methacholine test and were identified as risk factors.

Methacholine test, asthma, chronic cough, respiratory symptoms