Allergic rhinitis with or without concomitant asthma: difference in perception of dyspnoea and levels of fractional exhaled nitric oxide.
OBJECTIVE
Allergic rhinitis (AR) is a risk factor for developing clinical asthma. Moreover, AR is often associated with bronchial hyper-responsiveness (BHR). The aim of the present study was to investigate whether patients with AR and asthma differed from AR with or without BHR in degree of perception of dyspnoea and airway inflammation, measured as fractionated exhaled nitric oxide (NO).


METHODS
Twenty-nine patients with seasonal AR (timothy) were investigated with metacholine challenge test. Fourteen healthy non-reactive subjects served as controls.


METHODS
(1) Metacholine challenge test, cut-off value forced expiratory volume in 1 s (FEV(1)) PD20 2,000 microg. Slope value for metacholine was calculated as %fall in FEV(1)/mol metacholine. Dyspnoea during challenge was measured with a 10-graded modified Borg score. (2) Measurement of fractional-exhaled nitric oxide (FENO) at flow rate 50 mL/s.


RESULTS
Eighteen patients reported AR only, without asthma symptoms, and 12 (67%) were BHR. Eleven subjects had both rhinitis and asthma symptoms. Patients with rhinitis and asthma reported significantly more dyspnoea per percent fall in FEV(1) compared with those with rhinitis and BHR. Moreover, those with rhinitis and asthma had significantly higher NO values compared with those with rhinitis and BHR.


CONCLUSIONS
The difference between rhinitis patients with or without asthma symptoms seems to be mainly a question of perception of dyspnoea. However, FENO measurement indicates that dyspnoea may also be associated with increased inflammatory activity in the peripheral airways.
Aronsson
D
D
Institution of Clinical Medicine and Science, Department of Respiratory Medicine and Allergology, Lund, Sweden.
Tufvesson
E
E
Bjermer
L
L
D000328:Adult; D001249:Asthma / Q000150:complications* / Q000276:immunology / Q000503:physiopathology; D001980:Bronchi / Q000276:immunology / Q000503:physiopathology; D016535:Bronchial Hyperreactivity / Q000150:complications / Q000276:immunology / Q000503:physiopathology; D001985:Bronchial Provocation Tests / Q000379:methods; D004417:Dyspnea / Q000150:complications* / Q000276:immunology / Q000503:physiopathology; D005260:Female; D005541:Forced Expiratory Volume / Q000276:immunology / Q000502:physiology; D006801:Humans; D008297:Male; D016210:Methacholine Chloride / Q000276:immunology; D008875:Middle Aged; D009569:Nitric Oxide / Q000032:analysis*; D011058:Pollen / Q000276:immunology; D006255:Rhinitis, Allergic, Seasonal / Q000150:complications* / Q000276:immunology / Q000503:physiopathology; D012621:Seasons
D016210:Methacholine Chloride; D009569:Nitric Oxide