Extrinsic allergic alveolitis is a general term for type Ⅲ or Ⅳ allergic pneumonia caused by repeated inhalation of various antigenic organic dusts and low molecular weight chemicals in susceptible people. The lesions involve alveolar, pulmonary interstitial, and airway. The main clinical manifestations are cough, expectoration, and dyspnea. Clinically, extrinsic allergic alveolitis is classified into acute, subacute, and chronic forms. Extrinsic allergic alveolitis has a great impact on the pulmonary function of patients. Timely treatment will improve clinical symptoms and inhibit the development of disease. The current treatment plan is mainly avoiding exposure to antigen, glucocorticoid therapy, immunosuppressive therapy, anti-fibrotic therapy, and lung transplantation.
