METHACHOLINE PROVOCATIONS DO NOT REVEAL SENSITIVITY TO STRONG SCENTS

Background: It is common among patients with asthma to report sensitiv ity to strong scents. Provocations with methacholine are often used to verify this sensitivity. Objective: To evaluate the significance of m ethacholine provocations in asthmatic patients complaining about sensi tivity to strong scents, we compared sensitivity to methacholine and r eactions to provocation with perfume. Methods: Ten asthmatic patients having a PC20 less than 2 mg methacholine/mL were provoked with perfum e or saline on four occasions. On two occasions, the patients wore a n ose clip and underwent provocations with perfume for 5 and 30 minutes, respectively. On one occasion, the patients were provoked with perfum e but without a nose clip for five minutes. All patients were also sub jected to provocation with a placebo (saline). They were asked to esti mate their sensitivity to strong scents in connections with symptoms o f asthma. Results: No changes in lung function occurred after any of t he provocations with perfume compared with the baseline or with placeb o. Although all patients were very sensitive to methacholine, no relat ionship was found to their reported sensitivity to strong scents in co nnection with asthmatic symptoms. Conclusion: In this study, asthmatic patients who were very sensitive to methacholine were not affected by provocations with perfume. One may therefore question the value of pr ovocations with methacholine in patients complaining of symptoms after contact with strong scents.