The importance of basidiomycetous fungi cultured from the sputum of chronic idiopathic cough:. A study to determine the existence of recognizable clinical patterns to distinguish CIC from non-CIC

Background: Recently we have reported 5 cases of allergic fungal cough (AFC), which is intractable and is characterized by sensitization to one of basidiomycetous fungus. Because AFC shows good clinical response to antifungal drugs, diagnosing AFC in patients with CIC may lead to the consequent management of CIC. Therefore, we determined the incidence of CIC among our hospital patients, and the frequency of BM fungi in sputum samples collected from patients with CIC. Furthermore we evaluated whether or not a recognizable clinical pattern that distinguishes CIC from non-CIC exists. Methods: The medical records of 70 patients complaining of chronic cough who were referred to our hospital for diagnosis and treatment were analyzed retrospectively. Results: The primary diagnoses were CIC (27.0%), cough-variant asthma (30.0%), atopic cough (24.3%), sinobronchial syndrome (8.6%), cough-predominant asthma (7.1%), gastro-esophageal reflux (1.4%), and others (1.4%). In CIC patients, the median age, proportion of females, and frequency of acute upper respiratory tract infection did not differ significantly from those in non-CIC patients. CIC patients had a longer median duration of cough (11.0 months vs. 3.5 months). The positive ratio of BM cultured from the sputa of CIC patients (62.5%) was significantly (p = 0.0061) higher than that of non-CIC patients (16.7%). Conclusion: The existence of BM fungi in induced sputum may be an important factor for distinguishing the clinical manifestation of CIC from that of non-CIC. The clinical approach from the aspect of fungal allergy may serve as a clue that may aid in the successful management of CIC.