[A relapse of acute bird-related hypersensitivity pneumonitis due to the use of a feather duvet by a housemate].

In December 2007, a 78-year-old woman was admitted to our hospital complaining of cough and low-grade fever for 1 month. We performed various medical tests and diagnosed acute hypersensitivity pneumonitis. We suspected that the cause of illness was the prolonged use (10 years) of a feather duvet. She was treated with corticosteroids and was advised to avoid using feather duvets. This treatment improved her symptoms. However, she relapsed after 1 year. She had never used a feather duvet since the last admission, but her housemate used a feather duvet in the same room during winter. Bronchoalveolar lavage revealed lymphocytosis. Specific antibodies against pigeon and budgerigar-dropping extracts were present in her serum. On the basis of these findings, we diagnosed acute bird-related hypersensitivity pneumonitis. This condition is rarely caused by indirect exposure. Therefore, we reiterate the significance of obtaining of a detailed medical history to identify relevant antigens.