A case of humidifier lung potentially caused by Cryptococcuslaurentii.

Humidifier lung is a type of hypersensitivity pneumonitis caused by repeated inhalation of contaminated humidifier vapor containing antigens. Identification of specific antigens is crucial for the management of hypersensitivity pneumonitis. We report a case of humidifier lung in a 60-year-old man who presented with fever and dyspnea. Bacteriological examination of the humidifier identified Cryptococcus laurentii and antigen identification using the precipitating antibody method was positive for C. laurentii. Although C. laurentii is known to cause opportunistic infections, this case suggests that it may also be a potential causative antigen of humidifier lung in non-immunosuppressed individuals.