Immunologically mediated lung diseases. Extrinsic allergic alveolitis and allergic bronchopulmonary aspergillosis.

Early recognition and treatment of immunologically mediated diseases of the lung are vital to prevent irreparable damage. Extrinsic allergic alveolitis and allergic bronchopulmonary aspergillosis are often confused but should not be difficult to distinguish. The former is nonatopic and is marked by chills, fever, chest pains, cough, dyspnea, and restrictive pulmonary function. The immunologic hallmark is the presence of precipitating antibody to the suspected antigen. Allergic bronchopulmonary aspergillosis is atopic and is marked by low-grade fever, obstructive pulmonary function, markedly elevated serum IgE levels, and positive immediate and late response on skin tests. Both diseases respond well to early corticosteroid therapy. Prophylactic measures are also important in controlling extrinsic allergic alveolitis.