Methacholine provocations do not reveal sensitivity to strong scents.
BACKGROUND
It is common among patients with asthma to report sensitivity to strong scents. Provocations with methacholine are often used to verify this sensitivity.


OBJECTIVE
To evaluate the significance of methacholine provocations in asthmatic patients complaining about sensitivity to strong scents, we compared sensitivity to methacholine and reactions to provocation with perfume.


METHODS
Ten asthmatic patients having a PC20 less than 2 mg methacholine/mL were provoked with perfume or saline on four occasions. On two occasions, the patients wore a nose clip and underwent provocations with perfume for 5 and 30 minutes, respectively. On one occasion, the patients were provoked with perfume but without a nose clip for five minutes. All patients were also subjected to provocation with a placebo (saline). They were asked to estimate their sensitivity to strong scents in connections with symptoms of asthma.


RESULTS
No changes in lung function occurred after any of the provocations with perfume compared with the baseline or with placebo. Although all patients were very sensitive to methacholine, no relationship was found to their reported sensitivity to strong scents in connection with asthmatic symptoms.


CONCLUSIONS
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 provocations with methacholine in patients complaining of symptoms after contact with strong scents.
Millqvist
E
E
Asthma and Allergy Centre, University of Gothenburg, Sahlgrenska University Hospital, Sweden.
Löwhagen
O
O
D000328:Adult; D001249:Asthma / Q000276:immunology*; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects; D006801:Humans; D008297:Male; D016210:Methacholine Chloride / Q000494:pharmacology*; D009299:Nasal Provocation Tests; D010476:Perfume
D010476:Perfume; D016210:Methacholine Chloride