Asthma is characterized by cough and bronchial hyperresponsiveness (BHR), which are common symtom and sign in children with lower respiratory tract infection. Chlamydia pneumoniae (C. pneumoniae) and Mycomplasma pneumoniae (M. pneumoniae) casuses persistent cough and has been considered to be associated with asthma in previous studies. We investigate the characteristics of cough and BHR associated with C. pneumoniae and M. pneumoniae infection
The patients with persistent cough were performed allergy test, serologic tests for C. pneumoniae /M. pneumoniae and methacholine bronchoprovocation tests (MPT) from 2010 to 2015 were recruited. The subjects were divided into infection group and non-infection group based on the serologic findings and clinical records of C. Pneumoniae or M. Pneumoniae infection. Statistical analysis was performed using SPSS
Total of 112 patients were recruited. Number of infection group and non-infection group were 69, and 43, respectively. MPT were performed in 29 patients in infection group and 21 patients showed BHR (<16mg PC20 FEV1). Forty three of non-infection group were considered to have asthma (intermittent or mild persistent). There were no difference between two groups in terms of cough duration (5.1 vs 6.3 wks), atopy (specific IgE to inhalant allergen), methacholine PC20 FEV1 (11.7 vs 8.2 mg/mL), % Pred FEV1 (101.5 vs 100), FEV1/FVC (0.88 vs 0.88) and peripheral blood total eosinophil count (TEC) (213 vs 257/ÁL). Age of infection group was younger than non-infection group ( 5.9 vs 8.0 yr, P value=0.001). In this study, we found that younger age might be a risk factor for development of infection related BHR.