3.1. The etiological composition and cough character
Table 1 showed etiological composition and cough character of chronic cough. The number of children between 1 years and 3 years was 48 (11.4%), the number of children between 3 years and 6 years was 227 (54.0%), and the number of children between 6 years and 14 years old was 145 (34.5%).
Etiological composition of chronic cough: PIC is the most common (34.8%) cause of chronic cough in children of 1-14 years old, followed by UACS (22.9%), CVA (21.4%), AC (17.9%), TS (2.6%) and GERD (0.5%). Among these, in the young children (1-3 years old), the sequence of the common cause of chronic cough was PIC (35.4%), UACS (25.0%), CVA (16.7%), AC (18.7%), GERC (2.1%) and TS (2.1%). In the preschool children (3-6 years old), the sequence of the common cause of nonspecific chronic cough was PIC (37.9%), UACS (21.1 %), AC (19.8%), CVA (18.9%), TS (2.2%) and GERD (0.0%). In the school-age children (6-14 years old), the sequence of the common cause of nonspecific chronic cough was PIC (29.7%), CVA (26.9 %), UACS (34.8%), AC (14.5%), TS (3.4%) and GERD (0.7%). There was no significant difference in etiological components among different ages (P > 0.05).
In respect of cough character, 144 children (34.3%) were dry cough, and 276 children (65.7%) were wet cough. The common causes of wet cough were PIC (39.9%), UACS (26.1%), CVA (17.8%), AC (14.9%), TS (1.1%) and GERD (0.4%).The common causes of dry cough were CVA (28.5%), PIC (25.0%), AC (23.6%), UACS (16.7%), TS (5.6%) and GERD (0.7%).There was a significant difference in the cause of dry cough and wet cough (P<0.001) .