Bel Elisabeth H
Department of Pulmonary Diseases, Leiden University Medical Center, The Netherlands.
Curr Opin Pulm Med. 2004 Jan;10(1):44-50. doi: 10.1097/00063198-200401000-00008.
Asthma is a phenotypically heterogeneous disorder and, over the years, many different clinical subtypes of asthma have been described. A precise definition of asthma phenotypes is now becoming more and more important, not only for a better understanding of pathophysiologic mechanisms, but in particular to ascertain the specific genes associated with these phenotypes.
In children, three asthma phenotypes are now well defined: transient infant wheezing, nonatopic wheezing of the toddler, and IgE-mediated wheezing/asthma. Recently, a fourth phenotype, late-onset childhood asthma has been added to this list. In adults, asthma persisting from childhood into adulthood should be distinguished from asthma starting in adulthood. The phenotypes of adult-onset asthma are still poorly defined. Until now, phenotypic classification has been based primarily on etiologic factors (eg, aspirin sensitivity, persistent respiratory infections, occupational factors, or toxic exposures) or clinical characteristics of the disease (eg, mild, severe, brittle, near fatal, with fixed airflow obstruction, steroid resistant). Novel noninvasive techniques to assess the type and severity of airway inflammation and dysfunction are increasingly used to identify better the different phenotypes.
The classic phenotype of IgE-mediated asthma starting in childhood is now clearly defined. However, many other phenotypes of asthma in childhood as well in adulthood are being recognized. In particular, asthma starting in adulthood and noneosinophilic asthma constitute an important part of the adult asthma population, and are still poorly defined. A precise definition of these asthma phenotypes is urgently needed because they are likely to be associated with different genotypes, responses to treatment, and prognoses.
哮喘是一种表型异质性疾病，多年来已描述了许多不同的哮喘临床亚型。哮喘表型的精确定义现在变得越来越重要，这不仅有助于更好地理解病理生理机制，尤其有助于确定与这些表型相关的特定基因。
在儿童中，现已明确三种哮喘表型：短暂性婴儿喘息、幼儿非特应性喘息和IgE介导的喘息/哮喘。最近，迟发性儿童哮喘这一第四种表型也被列入其中。在成人中，应将从儿童期持续至成人期的哮喘与成人期起病的哮喘区分开来。成人起病哮喘的表型仍定义不清。到目前为止，表型分类主要基于病因因素（如阿司匹林敏感性、持续性呼吸道感染、职业因素或有毒物质暴露）或疾病的临床特征（如轻度、重度、脆性、近乎致命、伴有固定气流受限、激素抵抗）。评估气道炎症和功能障碍类型及严重程度的新型非侵入性技术越来越多地用于更好地识别不同表型。
儿童期起病的IgE介导的经典哮喘表型现已明确。然而，儿童期及成人期的许多其他哮喘表型也正在被认识到。特别是，成人期起病的哮喘和非嗜酸性粒细胞性哮喘构成了成人哮喘人群的重要组成部分，且仍定义不清。迫切需要对这些哮喘表型进行精确定义，因为它们可能与不同的基因型、治疗反应和预后相关。
