Bronchial hyperreactivity to histamine in aspirin sensitive asthmatics: relationship to aspirin threshold and effect of aspirin desensitisation.

Twenty seven aspirin sensitive asthmatic patients were studied to determine the relationship between non-specific bronchial responsiveness to inhaled histamine and the degree of sensitivity to aspirin (aspirin threshold dose). No correlation was found between provocative concentration of histamine (PC20H) and aspirin threshold dose. In 11 patients the influence of aspirin desensitisation on bronchial reactivity to inhaled histamine was examined. Mean PC20H measured the day after the patients were desensitised to 600 mg of aspirin did not change significantly from the values before desensitisation. These observations suggest that sensitivity to aspirin and non-specific bronchial hyperreactivity in asthmatic patients are independent phenomena.