Hypersensitivity pneumonitis

In this review, general details are presented about the clinical and laboratory presentation of hypersensitivity pneumonitis diseases that are included with the diffuse, interstitial lung disease group because alveolar walls and the supporting parenchyma are involved with inflammation. In chronic stages, granuloma and fibrotic changes develop. Several of the more common syndromes, such as farmer's lung and pigeon breeder's disease, are emphasized because more is known about the immunologic mechanisms operant in these diseases that contribute to injury of the lung.