The response of the airways to nasal stimulation in asthmatics with rhinitis

In twelve subjects with perennial allergic rhinitis and stable asthma nasal obstruction was induced with histamine diphosphate solution introduced onto the nasal mucosa by a nasal atomizer in a cumulative manner starting with a 0.001% solution. The effect on the nose was measured by the change in inspiratory nasal flow resistance and the lung response was determined by the one second forced expiratory volume (FEV1). The test was stopped when there was a greater than 20% fall in FEV1 or when the total dose of histamine diphosphate reached 26 mumoles. All twelve subjects had a greater than six fold increase in inspiratory nasal flow resistance together with other symptoms of rhinitis in response to histamine. Six subjects had a dose related fall of greater than 20% in FEV1. Two others had falls of 10% and 17%. These changes persisted for between five and thirty minutes. In four subjects, aerosol salbutamol was needed for complete reversal of the FEV1. There was no relationship between the fall in FEV1 resulting from nasal stimulation and airway reactivity as measured by histamine inhalation test on a separate day. The results suggest that the airways of some asthmatics narrow in response to nasal stimulation.