Bronchial sensitivity to inhaled histamine in healthy, nonatopic children.

Bronchial reactivity was determined in 38 healthy children by histamine inhalation challenge using forced expiratory and body plethysmographic methods. The histamine concentrations which produced a 20% decrease in forced expiratory volume in 1 second (PC20,FEV1), were comparable to the concentrations producing a 60% fall in specific airway conductance (PC60,SGaw). There was a significant difference in bronchial reactivity between the healthy children and a group of 29 asthmatic children (P less than 0.001), although there was some overlap. Bronchial reactivity in healthy children was found to be much higher than expected from surveys of adults. External influences or intrinsically increased bronchial reactivity in childhood are discussed as possible explanations.