Capsaicin provocation test in chronic cough in clinic / 国际儿科学杂志

Chronic cough in children is one of the most frequent reasons for consultation in clinic. The high cough sensitivity in most patients with chronic cough is difficult for treatment. Capsaicin,as the most com-monly used material for the test of cough sensitivity,is widely used in clinic. Capsaicin provocation test is more mature in foreign country,while in our country there is a few scholars applying it with the adult who suffered chronic cough,but few with children. This article reviews the process,chemical structure,nerve conduction,clini-cal operation,influence factors and safety of capsaicin provocation test.

Clinical features and cough sensitivity of patients with idiopathic chronic cough / 천식및알레르기

BACKGROUND: Chronic cough is a common clinical problem to which various etiologies are attributable; postnasal drip, asthma, gastroesophageal reflux (GER) and chronic bronchitis, However, in some cases, no particular etiology can be confirmed. OBJECTIVE: This study was aimed to evaluate cough sensitivity and the clinical manifestations of patients with idiopathic chronic cough. MATERIALS AND METHODS: We recruited 70 non-smoking patients who had been coughing for more than 3 weeks without any history, symptoms or signs of rhinitis, sinusitis, typical asthma, GER or recent upper respiratory infection episodes. Nineteen healthy controls were also enrolled. Bronchial provocation tests with methacholine, capsaicin and distilled water (DW) were performed. RESULTS: Thirteen patients were positive to rnethacholine test (PC20 < 25mg/ml) and defined as cough variant asthma. The others are classified into idiopathic chronic cough. By capsaicin and DW challenge tests, idiopathic cough patients could be divided into two groups, i.e., increased cough sensitivity (ICS) and normal cough sensitivity (NCS) groups. DW- induced cough counts were negatively correlated with C7 (lowest capsaicin concentration inducing continuous 7 or more coughs) (r=-0.739, p<0.001). No difference was found in clinical features such as age, sex, atopy, or peripheral eosinophil counts between these two groups but cough counts per cough burst were significantly higher in the ICS group. CONCLUSION: The heterogeneity in cough sensitivity of idiopathic chronic cough patients may refiect different pathophysiologic mechanisms. It is unclear whether patients with NCS merely have habitual or psychogenic cough or not. These suggest that different therapentic strategies should be established on idiopathic chronic cough patients according to cough sensitivity.