Abstract
Hypersensitivity pneumonitis (HP) is a complex pulmonary disorder mediated by the immune system and caused by various inhaled antigens against which the subject has previously been sensitized. In about 50% of the cases, the antigen is not identified. Identification and removal of the eliciting antigen is important for the prognosis. We report two cases of HP caused by molds and atypical mycobacteria isolated from wind instruments. We present the first case of HP caused by bassoon playing and another case of HP caused by molds in a trombone. HP caused by fungi and bacteria in wind instruments may be much more common than previously thought. HP caused by fungi and bacteria in wind instruments is probably underdiagnosed; this calls for more clinical attention when HP is suspected.