Bird Fancier's lung: An underdiagnosed etiology of dyspnea.

Bird Fancier's Lung is a type of hypersensitivity pneumonitis, an immunologically mediated lung disease due to repetitive exposure of air-borne avian antigen. This was first described in 1965 and is known as one of the most common causes of hypersensitivity pneumonitis. This case highlights this underdiagnosed etiology of dyspnea, disease presentation and exposure variability, and methods of diagnosis.