Bronchial hyperresponsiveness in preschool children with allergic rhinitis

Area of Science:

• Pediatric Allergy and Immunology
• Respiratory Medicine
• Immunology

Background:

• Allergic rhinitis in nonasthmatic children can present with bronchial hyperresponsiveness (BHR), a hallmark of asthma.
• The role of atopy in BHR development is significant in asthmatic patients.

Purpose of the Study:

• To evaluate BHR to methacholine (direct) and adenosine 5'-monophosphate (AMP; indirect) in preschool children with allergic rhinitis.
• To explore the association between the degree of atopy and BHR in this population.

Main Methods:

• Bronchial challenges with methacholine and AMP were conducted in 96 preschool children with allergic rhinitis.
• BHR was assessed using a modified auscultation method, determining endpoint concentrations for wheezing or oxygen desaturation.
• Atopy was quantified via serum total IgE, positive skin-prick tests (SPTs), and graded atopic scores.

Main Results:

• BHR to methacholine was found in 33.3% and to AMP in 27.1% of subjects.
• No significant link was found between BHR to methacholine and any atopy measure.
• Higher atopic scores correlated significantly with BHR to AMP, but not with serum IgE or SPTs.

Conclusions:

• A substantial proportion of preschool children with allergic rhinitis exhibit BHR to both direct and indirect stimuli.
• The degree of atopy, specifically atopic scores, is a relevant factor for indirect BHR (to AMP) but not for direct BHR (to methacholine).