[A CASE OF ACUTE EXACERBATION OF CHRONIC BIRDRELATED HYPERSENSITIVITY PNEUMONITIS WITH A REMARKABLE ELEVATION OF ENVIRONMENTAL AVIAN ANTIGEN LEVELS].

A man in his 60's with interstitial pneumonitis who was previously admitted to another hospital was transferred to our hospital for further investigations 6 years prior to an acute exacerbation. Given his history of avian contact, the presence of antibodies specific to avian antigen, and a positive result of the inhalation provocation test using pigeon dropping extracts, he was diagnosed with bird-related hypersensitivity pneumonitis (BRHP). As such, we instructed the patient to avoid exposure to avian antigen, and regularly measured the level of avian antigen in dust samples collected from his household environment. Despite avoiding the stimulus, corticosteroids and immunosuppressants were needed in view of progression of dyspnea after approximately five to six years. Four months after immunosuppressant therapy began, the patient suffered an acute exacerbation of BRHP and died. At this time, we found that the level of avian antigen was much higher than baseline. We suggest that exposure to high level of avian antigen is one cause of an acute exacerbation of BRHP.