Figure 1: A key event may be the development of vagal neuronal hypersensitivity in the airways. Commonly associated diseases like rhinitis, eosinophilic airway inflammation, or classical acidic reflux may be triggers to lower thresholds for peripheral cough reflex activation. Nasal afferent stimulation may not directly initiate the cough reflex, but modulate (sensitize or desensitize) the cough reflex depending on the type of nasal stimulus. Gaseous reflux has been hypothesized to be a common factor to develop cough hypersensitivity. TRP, transient receptor potential. (Modified from Woo-Jung Song et al., Asia Pac Allergy 2014; 4: 3-13)