Background: Adult-onset asthma is frequently associated with antecedent respiratory symptoms that could represent either previously undiagnosed asthma or previous lung infections that result in subsequent asthma. To further investigate a reported association of Chlamydia pneumoniae infection and adult reactive airway disease, we looked for evidence of atypical infections in patients with acute wheezing and nonwheezing respiratory illnesses.
Methods: Pharyngeal cultures and acute and convalescent serology for C pneumoniae and Mycoplasma pneumoniae were obtained from 131 primary care outpatients (mean age, 36 years) with acute wheezing or nonwheezing respiratory illnesses. Peak flow measurements were obtained in patients with cough or wheeze. Spirometry before and after bronchodilator use was obtained to substantiate the diagnosis of chronic asthma in patients who had persistent wheezing and dyspnea after enrollment.
Results: Twelve (9.2%) of 131 patients were classified as having chronic asthma, 5/12 developed chronic asthma for the first time during the study period. Thirty (22.9%) patients were classified with acute asthmatic bronchitis, and 89 (67.9%) had nonwheezing illness. Two of the newly diagnosed asthmatics met serologic criteria for acute C pneumoniae infection, and one had serologic evidence for acute M pneumoniae infection. Compared with patients with nonwheezing respiratory illnesses, C pneumoniae seroreactivity was significantly (P < .001) associated with both chronic asthma and with acute asthmatic bronchitis.
Conclusions: Acute wheezing illness was encountered frequently in this primary care setting. Although most acute wheezing respiratory illness resolved without obvious chronic sequelae, some patients had persistent symptoms and were diagnosed with chronic asthma. C pneumoniae seroreactivity was associated with both acute and chronic wheezing, suggesting that pulmonary infection with this intracellular pathogen plays a role in the natural history of reactive airway disease.