过敏性肺炎是吸入抗原引起的肺变态反应性疾病。急性变态反应一般无后遗症,长期小量接触抗原可形成间质性肺疾病,某些病例发展成肺间质纤维化。肺活检组织可见炎症累及小间隙、肺泡间隙和呼吸道末端的周围组织,在这些组织常含有多核组织细胞上皮样肉芽肿。过敏性肺炎的发病机制尚不完全清楚,最近由于广泛应用支气管肺泡灌洗(BAL)技术, Allergic pneumonia is a pulmonary allergic disease caused by inhaled antigens. Acute allergic reactions generally no sequelae, long-term exposure to small amounts of antigen can form interstitial lung disease, some cases of pulmonary interstitial fibrosis. Lung biopsy shows inflammation involving the small gap, alveolar space and the surrounding tissue of the respiratory tract, in these tissues often contain multinucleated cell epithelial-like granuloma. The pathogenesis of allergic pneumonia is not fully understood, the recent due to the widespread use of bronchoalveolar lavage (BAL) technology,