[Proportion of incidence of etiological agents in children with non-specific chronic cough in Chongqing: a follow-up study].

Objective: To investigate the proportion of incidence of children with non-specific chronic cough in Chongqing and analyze the characteristics of etiology during the follow-up.

Method: Diagnostic criteria were defined for children with non-specific chronic cough according to the Guidelines of diagnosis and therapy for children with chronic cough that were formulated by the Subspecialty Group, Society of Pediatrics, Chinese Medical Association and Chinese Journal of Pediatrics in 2008. Totally 266 patients in whom cough was the main or the only symptom,lasting > 4 weeks, presenting to Asthma Center of Children's Hospital, Chongqing Medical University between June 2008 and April 2009 were recruited into this study. Based on the Guidelines, diagnosis was made after taking history, physical examination and assistant examination. After etiological treatment, the patients were followed up during the second week, the fourth week and the twelfth week. Etiological diagnosis was confirmed if cough was resolved after specific therapy. If cough was not resolved,the diagnosis was rechecked and a new therapy was applied.

Result: Totally 125 (47.0%) patients received final diagnoses of cough variant asthma (CVA), 58 (21.8%) was CVA and upper airway cough syndrome (UACS), 44 (16.5%) was diagnosed postinfection cough, 35 (13.2%) of UACS. In different age groups, the proportion of incidence of etiological agents is statistically distinct. In the ≤ 3 years old group, 35 patients (70.0%) were diagnosed CVA, 10 (20.0%) was postinfection cough; in 3 - 6 years group, 71 patients (50.7%) had CVA; the incidence of UACS was significantly higher in ≥ 6 years group.

Conclusion: It is concluded that CVA, CVA and UACS, post infection cough, and simple UACS were identified as the three top reasons for children with chronic cough in Chongqing. Children with chronic cough of different age groups had different etiology of cough. The characteristic of each etiology need further study.