title: Allergen-induced increase in non-allergic bronchial reactivity.
abstract: Non-allergic bronchial hyper-reactivity is a feature of most patients with asthma. We have measured non-allergic bronchial reactivity to inhaled histamine and methacholine in thirteen asthmatic subjects before and after allergen inhalation in the laboratory. The allergen inhalation produced mild early asthmatic responses (19-40% FEV1 fall) in all thirteen, additional definite late asthmatic responses (17-29% FEV1 fall) in four, and equivocal late asthmatic responses (5-11% FEV1 fall) in five. Following allergen inhalation, non-allergic bronchial reactivity increased in seven for up to 7 days. The seven included all four with definite late asthmatic responses and three of the five with equivocal late asthmatic responses. We conclude that allergens make asthma worse, partly through non-allergic mechanisms, and that avoidance of allergens is important in reducing non-allergic bronchial hyper-reactivity.
mesh_terms: D000485:Allergens; D001249:Asthma / Q000150:complications / Q000175:diagnosis / Q000209:etiology*; D005541:Forced Expiratory Volume; D006632:Histamine; D006801:Humans; D008688:Methacholine Compounds; D013997:Time Factors
chemical_list: D000485:Allergens; D008688:Methacholine Compounds; D006632:Histamine