The role of Airway Hypersensitivity: relevance in Allergy
The theory of airway hypersensitisation posits a heightened sensitivity in laryngeal and pharyngeal tissues as a potential aetiological factor for UCTS[4 , 6 , 11 , 49-54 ]. Underlying this theory is the concept that peripheral and/or central sensitization of neuronal pathways results in exaggerated afferent nerve activity, transforming normally non-noxious stimuli into distressing symptoms[11 , 28 , 55 , 56 ]. This state may arise from an initial insult including viral infection, allergy, or acid reflux, but persists even after the resolution of the original trigger, and is likely modulated by complex biopsychosocial factors. Consequently, the sensitized airway tissues may be reactive to various dietary, endogenous and environmental irritants and in some cases by innocuous stimuli (such as phonation or emotion), leading to persistent, often refractory symptoms that defy conventional diagnostic categorization and therapeutic approaches. The role of allergy in precipitating or contributing to somatosensory aberrations, or indeed the role of sensitisation in the occurrence or expression of throat symptoms in this group is poorly understood at present.