Nasal Hyperreactivity to Methacholine Test in Perennial Allergic Rhinitis

ABSTRACT

Although histamine and methacholine challenge tests are commonly used to evaluate the hypersensitivity in allergic rhinitis, some controversies still remain to standardize the test. This study was designed to evaluate the usefulness of the methacholine challenge test for the evaluation of hyperreactivity in allergic rhinitis. Twenty three patients with perennial allergic rhinitis and 17 normal subjects were included in this study. All subjects underwent saline nasal challenge and methacholine nasal challenge test with different doses (6 mg, 12 mg, 24 mg / in 0.5 ml of saline). We measured the nasal cavity volume by acoustic rhinometry in each step and counted the number of sneezes for 15 minutes. The volume of nasal secretion was also measured by tissue paper method. Besides that, we compared the data between allergic patients with a short (under 1 year) and long duration (more than 1 year). There were no differences in the frequency of sneezing and nasal volume change to each amount of methacholine in both groups. Nasal secretion increased after methacholine challenge in both groups. However, the allergic group showed significant increase after the methacholine challenge of 12 mg compared to the control group. And the volume of nasal secretion significantly increased in patients with a long duration. The nasal methacholine challenge test can be used as a diagnostic tool to detect hyperreactivity in perennial allergic rhintis. The optimal dilution was 12 mg (in 0.5 ml of saline) for the nasal methacholine challenge test.