Hypersensitivity pneumonitis from residential composting: residential composter's lung.

Hypersensitivity pneumonitis results when a susceptible individual is exposed to sufficient airborne material capable of inducing a systemic and pulmonary immune response. We describe a man who had all the classic manifestations of hypersensitivity pneumonitis but in whom the circumstances of sensitization, residential yard work with composted yard clippings, has not previously been reported. We call this new entity residential composter's lung.