Bronchial responsiveness to methacholine is increased in citrus red mite (Panonychus citri)-sensitive children without asthmatic symptoms.
BACKGROUND
A recent investigation has suggested that citrus red mite (Panonychus citri, CRM) is a common sensitizing allergen among children living around citrus farms.


OBJECTIVE
A cross-sectional survey was performed to evaluate the bronchial responsiveness to methacholine in CRM-sensitive children without asthmatic symptoms.


METHODS
A total of 375 children living around citrus farms were enrolled in this study. There were 201 boys and 174 girls with a mean age of 12.5 (range 7-16) years. Each subject was evaluated by a questionnaire, a skin prick test with 13 common inhalant allergens including CRM, and a methacholine bronchial provocation test (MBPT).


RESULTS
Positive rate of MBPT (PC20-methacholine < 25 mg/mL) was higher in atopic rhinitic and atopic control children than in nonatopic rhinitic and nonatopic control subjects (41.3% and 33.3% vs 17.2% and 15.4%, respectively, both P < 0.05). Slope of dose-response curve (DRS, %/mg/mL) was higher in atopic rhinitic children than in nonatopic rhinitic, atopic control and nonatopic control subjects (14.3 +/- 0.87 vs 9.4 +/- 0.72, 10.0 +/- 1.37 and 9.2 +/- 1.51, P < 0.05, respectively). Both the positive rate of MBPT and the DRS were increased in children with positive skin response to CRM than in those without sensitization (48.2% vs 22.9%, P = 0.0001; 15.6 +/- 1.26 vs 10.2 +/- 0.65, P = 0.0001).


CONCLUSIONS
Bronchial responsiveness is increased in citrus red mite-sensitive children even if they have no asthmatic symptoms.
Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
K U
KU
Min
Y K
YK
Kim
H S
HS
Park
M H
MH
Lee
B J
BJ
Lee
J W
JW
Son
Y Y
YY
Kim
S H
SH
Cho
D000293:Adolescent; D000485:Allergens / Q000276:immunology; D000818:Animals; D001249:Asthma / Q000175:diagnosis / Q000276:immunology; D016535:Bronchial Hyperreactivity / Q000150:complications* / Q000175:diagnosis; D001985:Bronchial Provocation Tests; D002648:Child; D002957:Citrus / Q000469:parasitology; D004306:Dose-Response Relationship, Immunologic; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000150:complications / Q000469:parasitology; D008297:Male; D016210:Methacholine Chloride; D012220:Rhinitis / Q000150:complications / Q000469:parasitology; D012307:Risk Factors; D012882:Skin Tests; D014324:Trombiculidae / Q000276:immunology*
D000485:Allergens; D016210:Methacholine Chloride