Cough Hypersensitivity Syndrome: A Few More Steps Forward

Abstract

Cough reflex is a vital protective mechanism against aspiration, but when dysregulated, it can become hypersensitive. In fact, chronic cough is a significant medical problem with a high degree of morbidity. Recently, a unifying paradigm of cough hypersensitivity syndrome has been proposed. It represents a clinical entity in which chronic cough is a major presenting problem, regardless of the underlying condition. Although it remains a theoretical construct, emerging evidence suggests that aberrant neurophysiology is the common etiology of this syndrome. Recent success in randomized clinical trials using a P2X3 receptor antagonist is the first major advance in the therapeutics of cough in the past 30 years; it at last provides a strategy for treating intractable cough as well as an invaluable tool for dissecting the mechanism underpinning cough hypersensitivity. Additionally, several cough measurement tools have been validated for use and will help assess the clinical relevance of cough in various underlying conditions. Along with this paradigm shift, our understanding of cough mechanisms has improved during the past decades, allowing us to continue to take more steps forward in the future.

Keywords: Cough; hypersensitivity; pathophysiology.

Fig. 1. Paradigm of cough hypersensitivity syndrome. This represents a clinical entity where chronic cough is a major presentation, irrespective of underlying conditions. Modified with permission from Asia Pac Allergy 2014;4:3-13.

Fig. 2. Current potential therapeutic targets in cough hypersensitivity syndrome.