Nasal histamine challenges in symptomatic allergic rhinitis

Abstract

Twenty subjects (seven with perennial allergic rhinitis, seven with symptomatic seasonal allergic rhinitis, and six normal control subjects) underwent assessment of nasal sensitivity to histamine. Nasal resistance was measured by posterior rhinometry under control conditions and after log incremental doses of histamine solution pipetted into the nose (0.5 to 5000 μg). Allergic subjects exhibited a twofold rise of nasal resistance with doses of 0.5, 5, or 50 μg of histamine, whereas the nasal resistance in normal subjects remained unchanged until 500 or 5000 μg of histamine had been administered. Nasal reactivity to histamine was not correlated with symptoms on the day of testing but was correlated with the number of positive wheals to skin prick testing. It was concluded that nasal resistance is more sensitive to histamine in subjects with allergic rhinitis than in normal control subjects and that this difference may be used as the basis of a diagnostic test.