【定义和患病率】哮喘是一种以气管、支气管对各种刺激物的反应性增高,从而导致广泛的气道狭窄为特征的疾病。其病变可自然缓解,亦可经治疗而逆转。近年来公认的关于哮喘的定义并不指明病因,亦不确定临床和病理的特征,也不涉及不同的免疫机制,而只是描述了所有哮喘病人共有的基本的异常——可逆性的气管、支气管平滑肌的高反应性。 [Definition and prevalence] Asthma is a condition characterized by increased tracheal, bronchial reactivity to various stimuli leading to extensive airway stenosis. The lesion can be naturally relieved, but also can be reversed by treatment. The widely accepted definition of asthma in recent years does not specify the etiology, nor the clinical and pathological features, nor the different immune mechanisms involved. It merely describes the basic anomalous-reversible trachea and bronchus common to all asthmatics Smooth muscle hyperresponsiveness.