A clinical study of hypersensitivity pneumonitis presumably caused by feather duvets.

Background: Bird fancier's lung (BFL) is a type of hypersensitivity pneumonitis induced by the inhalation of bird-related antigens. The BFL induced by feathers is difficult to diagnose because feathers are generally unrecognized as a causative antigen.
Objective: To determine the clinical features of BFL presumably induced by feather duvets (feather duvet lung) to provide clues for diagnosis.
Methods: We performed a retrospective review of the medical records of patients with feather duvet lung evaluated between April 1, 2000, and June 30, 2003, at the Tokyo Medical and Dental University Hospital in Japan.
Results: Seven patients with feather duvet lung were included in this study; 4 patients had acute disease and 3 had chronic BFL. Duration of contact with feather duvets was 1 month to 10 years. Serum KL-6 and surfactant protein D levels were elevated in all the patients. Specific antibodies against avian antigens were positive in acute BFL but negative in chronic BFL. Antigen-induced lymphocyte proliferation in peripheral blood or bronchoalveolar lavage cells was positive in all the patients. The diagnosis was confirmed by an environmental or inhalation provocation test.
Conclusions: Feather duvets can induce acute and chronic BFL. Physicians should be aware of feather duvets as a cause of BFL because feather duvets are becoming more prevalent.