Nasal response in subjects undergoing challenges by inhaling occupational agents causing asthma through the nose and mouth.
BACKGROUND
Subjects with occupational asthma (OA) often report nasal symptoms, but nasal reactions to inhalation challenges with occupational agents have not been well characterized.


METHODS
Fifteen subjects with OA (eight due to high-molecular-weight agents--flour and guar gum--and seven due to isocyanates) underwent inhalational challenges using closed-circuit devices (dry particles for high-molecular-weight agents and gas generator for isocyanates) on two occasions, 2-4 weeks apart in a random fashion. On one occasion, they inhaled through the nose and, on another, through the mouth. The FEV1 was monitored for up to 8 h afterward, and symptoms were documented with a standardized questionnaire on nasal symptomatology, assessment of nasal resistance by rhinomanometry, and nasal lavage for the examination of cells and mediators.


RESULTS
Inhaling through the mouth and through the nose: 1) yielded similar asthmatic responses (25+/-8% and 22+/-10% maximum changes in FEV1) 2) more than doubled the peak nasal symptoms and nasal resistance when the maximum daily response was compared with prechallenge results. This increase occurred on the days of inhalational challenges through the mouth and through the nose. There were some significant responses assessed by nasal lavage in terms of cells and mediators, again with no differences between the days of challenges through the mouth and through the nose.


CONCLUSIONS
Inhaling occupational agents of high or low molecular weight, including isocyanates, whether through the mouth or nose: 1) results in a similar asthmatic response 2) causes a significant nasal response in terms of symptoms and an increase in nasal resistance 3) causes some significant changes in inflammatory cells and mediators.
Desrosiers
M
M
Department of Otorhinolaryngology, Centre hospitalier universitaire de Montréal (CHUM), Montreal, Canada.
Nguyen
B
B
Ghezzo
H
H
Leblanc
C
C
Malo
J L
JL
D000280:Administration, Inhalation; D000328:Adult; D000485:Allergens / Q000009:adverse effects*; D001249:Asthma / Q000209:etiology* / Q000503:physiopathology; D005260:Female; D005433:Flour / Q000009:adverse effects; D005541:Forced Expiratory Volume; D005685:Galactans / Q000009:adverse effects; D006801:Humans; D008297:Male; D008351:Mannans / Q000009:adverse effects; D008875:Middle Aged; D009061:Mouth Mucosa / Q000503:physiopathology*; D009297:Nasal Mucosa / Q000503:physiopathology*; D009299:Nasal Provocation Tests / Q000009:adverse effects*; D009784:Occupational Diseases / Q000209:etiology* / Q000503:physiopathology; D016273:Occupational Exposure / Q000009:adverse effects*; D053149:Plant Gums; D014051:Toluene 2,4-Diisocyanate / Q000009:adverse effects
D000485:Allergens; D005685:Galactans; D008351:Mannans; D053149:Plant Gums; D014051:Toluene 2,4-Diisocyanate; C007894:guar gum