Nasal and bronchial histamine reactivity in patients with allergic rhinitis out of season

Background: The correlation between non-specific hyperreactivity of upper and lower airways in pathologic conditions has not been studied extensively. Objective: To investigate the occurrence of nasal and bronchial hyperreactivity in patients with allergic rhinitis studied out-of-season. Methods: From patients admitted to the Allergy Unit at Stockholm Slider Hospital, 12 individuals with allergic rhinitis due to grass or birch pollen were selected. The nasal mucosa was exposed to increasing concentrations of histamine chloride and the response was recorded by rhinostereometry, an optical method that exclusively measures changes in nasal congestion. Bronchial histamine challenge was performed in connection with the nasal tests, but on different days. Results: The nasal histamine response was significantly greater than in a reference group of healthy volunteers (P < .01). Nasal hyperreactivity was demonstrated in 9 of 12 patients. No clear relation between the magnitude of nasal and bronchial histamine responses was seen in the study group. Conclusions: In allergic rhinitis studied out-of-season, airway hyperreactivity is common in both upper and lower airways, but does not necessarily occur together in the same individual.