2.4 Methods
The diagnosis of the etiology of all children with non-specific chronic
cough was referenced to the diagnosis and differential diagnosis of
chronic cough in children guidelines[1,5].Each of the patients
underwent the following procedures for the investigation of the cause of
cough: 1) detailed recording of medical history(duration and nature of
the cough, associated symptoms, the history of medication, family
history of allergic disease or related disease and information about the
living environment of the patient); 2) detailed physical examination
with particular attention to the heart and lower and upper airways; and
3) Allergen test, Pulmonary function assessment, chest X-ray
examination/further chest computed tomography (CT) examination, nasal
endoscopy, bronchoscopy and bronchoalveolar lavage fluid cytology and
pathogen isolation and culture or ethacholine-challenge test in patients
with suspicious symptoms or signs.