支气管哮喘的病因和发病机理尚未完全明了,目前大多数人倾向于认为哮喘是一种多因子遗传病,其遗传度在70～80%左右。对哮喘的分类,一般公认为两类,即外源性哮喘和内源性哮喘。外源性哮喘者常于幼年发病,具有明显的对多种过敏原的变态反应史。内源性哮喘者常于成年发病,具有支气管迷走神经反 The etiology and pathogenesis of bronchial asthma is not yet fully understood, at present most people tend to think that asthma is a multifactorial genetic disease, the heritability of about 70 to 80%. The classification of asthma, generally recognized as two categories, namely extrinsic asthma and endogenous asthma. Exogenous asthma often onset in infancy, with a clear history of allergies to a variety of allergens. Endogenous asthma are often in adult onset, with bronchial vagal reverse