Diagnosis and Treatment of Unexplained/Refractory Chronic Cough (UCC/RCC)

Abstract

　Cough is categorized as acute, subacute, and chronic. The three major causes of chronic cough in Japan are cough variant asthma, gastroesophageal reflux disease, and sinonasal-bronchial syndrome. However, patients with unknown causes or ineffective treatment are frequently encountered.

　Difficult-to-treat chronic cough, which is considered refractory, is categorized as follows: 1) unexplained chronic cough in patients with unknown underlying disease and 2) refractory chronic cough in patients with identified underlying disease that remains resistant to appropriate treatment. Furthermore, a new concept of cough, known as cough hypersensitivity syndrome has been proposed to explain the common pathophysiology of treatment-resistant cough, which is independent of conventional underlying diseases.