Asthma

Abstract

Definition Asthma is easily recognized in a young patient who had eczema in infancy and now complains of paroxysmal dyspnoea with wheezing, provoked by inhaled allergens or exercise. Differences of opinion arise when persistent dyspnoea and wheezing in middle age is associated with eosinophilia and is relieved by corticosteroids. Although there is no generally agreed definition, it is widely accepted that the characteristic feature of asthma is narrowing of the intrathoracic airways (recognized by dyspnoea, wheezing or respiratory measurements), varying in severity over short periods of time. The aetiology, be it allergy or some other factor, is thus left open. It is permissible to adopt other definitions which lay more stress on hypersensitivity to allergens or response to corticosteroids, provided that the criteria are clearly stated.