Relationship of airway symptoms from chemicals to capsaicin cough sensitivity in atopic subjects.
BACKGROUND
It is well known that some patients with allergy complain of airway symptoms from chemicals (ASCs) and strong odours. However, the importance of such information for the treatment of allergic disease is not known. Such symptoms in non-allergic patients have previously been shown to be related to increased sensory nerve reactivity, which is expressed as increased cough sensitivity to inhaled capsaicin.


OBJECTIVE
The aim of this study was to examine ASC in atopic patients and relate it to cough reaction to capsaicin inhalation.


METHODS
Fifty-seven consecutively chosen, skin prick-positive patients with symptoms of the upper and/or lower airways completed a questionnaire concerning ASC. The patients were then divided into two groups, those with and those without such symptoms. Both groups were provoked with inhaled capsaicin in three increments and compared with 73 healthy control subjects.


RESULTS
Out of 57 atopic patients, 34 reported ASC agents and 23 did not. The patients with ASC were older (P<0.01) and coughed significantly more on capsaicin provocation (P<0.001), but did not differ from them with respect to the allergic disease or its treatment or to smoking habits. Patients with atopy but without ASC did not differ from healthy controls with regard to sensitivity to capsaicin inhalation. The scored degree of ASC was directly related to the number of coughs during the capsaicin provocation.


CONCLUSIONS
ASC in atopic patients are related to increased airway sensory nerve reactivity. There is still no explanation for this in certain patients with atopy, but age may be a confounding factor.
Millqvist
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E
Asthma and Allergy Research Group, Sahlgrenska University Hospital, Gothenburg, Sweden. eva.millqvist@medfak.gu.se
Johansson
A
A
Bende
M
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D001985:Bronchial Provocation Tests / Q000379:methods; D002211:Capsaicin; D003371:Cough / Q000209:etiology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000150:complications; D008297:Male; D008875:Middle Aged; D018777:Multiple Chemical Sensitivity / Q000150:complications*; D012130:Respiratory Hypersensitivity / Q000150:complications*; D012307:Risk Factors
D002211:Capsaicin