Extrinsic allergic alveolitis/hypersensitivity pneumonitis: a world perspective from Japenese and Canadian data

We review the recent progress in clinical studies of extrinsic allergic alveolitis (EAA)/hypersensitivity pneumonitis (HP) in a world perspective. On the basis of our data, we describe: (1) agricultural environments and causative antigens, focusing on the ecology of antigenic microorganisms; (2) new diagnostic approaches: diagnostic criteria, high-resolution computed tomography and polymerase chain reaction; (3) long-term outcome and factors relating to poor prognosis; and (4) erythromycin, a potential drug for new therapy. In conclusion, we stress that the correct diagnosis and careful follow-up are still indispensable for a satisfactory outcome of EAA.