Nasal histamine challenges in symptomatic allergic rhinitis

Area of Science:

• Immunology
• Otolaryngology
• Allergy Research

Background:

• Allergic rhinitis involves heightened nasal responses.
• Histamine is a key mediator in allergic reactions.
• Quantifying nasal sensitivity to histamine is crucial for understanding allergic rhinitis.

Purpose of the Study:

• To assess and compare nasal sensitivity to histamine in patients with allergic rhinitis and healthy controls.
• To investigate the relationship between nasal reactivity, allergy symptoms, and skin test results.

Main Methods:

• Posterior rhinometry was used to measure nasal resistance.
• Log incremental doses of histamine (0.5 to 5000 micrograms) were administered intranasally.
• Subjects included those with perennial allergic rhinitis, seasonal allergic rhinitis, and normal controls.

Main Results:

• Allergic subjects showed a twofold increase in nasal resistance at lower histamine doses (0.5-50 micrograms) compared to controls.
• Normal subjects required significantly higher histamine doses (500-5000 micrograms) to show a similar increase in nasal resistance.
• Nasal histamine reactivity correlated with positive skin prick test wheals but not with daily symptoms.

Conclusions:

• Nasal resistance is demonstrably more sensitive to histamine in individuals with allergic rhinitis.
• The heightened nasal sensitivity to histamine in allergic rhinitis patients presents a potential diagnostic marker.
• This finding suggests a basis for developing a novel diagnostic test for allergic rhinitis.