Risk factors influencing bronchial hyperresponsiveness to methacholine in school age and adolescence of atopic dermatitis

Purpose: Many studies have shown the importance for bronchial hyperresponsiveness(BHR) in children with bronchial asthma and allergic rhinitis. However, studies have not been done in BHR in school age and adolescence with atopic dermatitis(AD). Methods: The patients with history of bronchial asthma were excluded and methacholine challengetest (MCT) was performed in 103 children with atopic dermatitis. The positive of MCT result is defined as provocative concentration of methacholinecausing a 20% fall in forced expiratory volume in 1 second (PC20)≤ 8 mg/mL. According of the level of PC20, the patients were divided into two groups. Results: The group 1 (BHR+) was observed in 43 of all patients (41.7%). Of two groups, significant differences were observed in age, body mass index. No significant differences were observed in the number of male, SCORing Atopic Dermatitis( SCORAD) index, admission history, smoking exposure history, other allergic disease, parental allergic disease. The group 1 (BHR+) have higher levels of total eosinophil count compared with the group 2 (BHR–) (629.8± 360.5/μL vs. 470.2± 253.9/μL, P= 0.01). But no significant association was found between severity of BHR and SCORADscore, total immunoglobulin E, total eosin ophil count and eosinophil cationic protein(r= 0.008, P= 0.961; r= –0.217, P= 0.162; r= 0.225, P= 0.147; r= –0.032, P= 0.841). The list of allergen is that the house dust mite, tree, weed, food, animal hair, and fungus. The house dust mitehas correlation with bronchial hypersensitivity statistically and the any of allergen groups, either. Conclusion: No significant relationship was observed between degree of BHR and allergy laboratory finding, severity of AD. (Allergy Asthma Respir Dis 2014;2:179-186)