STUDIES ON THE RELATIONSHIPS BETWEEN SENSITIVITY TO COLD, DRY AIR, HYPEROSMOLAL SOLUTIONS, AND HISTAMINE IN THE ADULT NOSE

We have previously reported that elevated osmolality of nasal secretions is linked to the rhinitic reaction to cold and dry air (CDA) that results in inflammatory mediator release and that nasal challenge with hyperosmolal solutions can induce histamine release in randomly selected individuals. These findings led to a comparison of the effect of nasal challenge with hypertonic fluid in 11 subjects who demonstrated a nasal response to CDA compared to 10 subjects without CDA sensitivity. All volunteers were challenged with isosmolal (300 mosmol/kg H2O) and hyperosmolal (800 mosmol/kg H2O) mannitol solutions. Their response was evaluated by symptom scores and quantification of histamine in nasal lavages. CDA responders differed significantly from non-responders in terms of both the total amount and the concentration of histamine in the lavage following hyperosmolal challenge (p<0.04 and p<0.02, respectively). In addition, CDA responders reported a higher change from baseline for nasal congestion, pruritus, and lacrimation following hyperosmolal challenge, but the scores for rhinorrhea, the volume of the returned nasal lavage fluid following hyperosmolal challenge, and the capacity to reduce the osmolality of the administered hyperosmolal fluid did not differ. Allergic status was not a factor in hyperosmolal reactivity. To investigate possible differences in nonspecific nasal mucosal sensitivity that could account for these findings, all subjects underwent provocation with five increasing doses of histamine, from 0.01 to 1 mg. No significant difference between CDA responders and nonresponders in symptomatology or in the induction of vascular permeability, as assessed by TAME-esterase activity in nasal fluids, could be demonstrated. These findings suggest that CDA responders may have increased nasal mast cell releasability to hypertonic stimuli but their end-organ reactivity is not enhanced.