title: Precipitating factors of asthma.
abstract: Asthma is characterised by bronchial hyperresponsiveness. This feature of the asthmatic diathesis predisposes patients to wheezing in response to a number of different factors. These precipitating factors include specific allergen acting via sensitised mediator cells through an IgE-dependent mechanism. There are irritants which may work through a non-specific manner, or stimuli such as exercise and hyperventilation, which probably also act through mediator release via a non-IgE-dependent manner. The mechanism whereby physical stimuli such as exercise induce bronchoconstriction is of interest, because it increases the context in which the mast cell may participate in acute asthmatic bronchoconstriction. Respiratory infections also commonly provoke asthma, especially in infants and may, indeed, precipitate the asthmatic state itself. Finally, drugs can often trigger asthma attacks and the mechanisms of asthma precipitated by non-steroidal anti-inflammatory drugs such as aspirin have been the subject of recent research.
authors.affiliation: Department of Allergy & Allied Respiratory Disorders, UMDS Guy's Hospital, London, UK.
authors.forename: T H
authors.initials: TH
authors.lastname: Lee
mesh_terms: D000397:Air Pollution / Q000009:adverse effects; D000485:Allergens / Q000276:immunology; D001241:Aspirin / Q000009:adverse effects; D001249:Asthma / Q000209:etiology*; D001250:Asthma, Exercise-Induced / Q000209:etiology; D002648:Child; D006801:Humans; D014777:Virus Diseases / Q000150:complications
chemical_list: D000485:Allergens; D001241:Aspirin