In school-aged children, the early-onset persistent bronchial hyperresponsiveness (BHR) phenotype differs from the late-onset BHR phenotype, with the former associated with a high atopic burden and increased risk for newly diagnosed asthma, and the latter associated with allergic rhinitis symptoms and later sensitization, according to a study published in the Annals of Allergy, Asthma & Immunology.
Eun Lee, MD, PhD, of the Department of Pediatrics, Chonnam National University Hospital, Chonnam National University Medical School in Gwangju, Korea, and colleagues analyzed data from 1305 elementary school children from the 4-year prospective Children’s Health and Environmental Research (CHEER) study. At each follow-up visit, the investigators measured total serum immunoglobulin E levels and blood eosinophil levels and performed an allergy workup that included methacholine challenge tests and conducting an ISSAC (International Study of Asthma and Allergies in Childhood) questionnaire.
Investigators identified four BHR phenotypes — non-BHR (72.2%), early-onset transient BHR (15.4%), late-onset BHR (6.7%), and early-onset persistent BHR (5.7%). Early-onset was defined as the presence of BHR at baseline (ages 6-7) as confirmed by methacholine challenge test, and late-onset BHR was defined as no BHR at baseline but positive BHR at the final visit. Participants were followed for 4 years at 2-year intervals beginning at age 6 to 8.
There were no significant differences in BHR phenotypes between boys and girls. The authors found that the blood eosinophil count and total serum immunoglobulin E levels were highest in children with the early-onset persistent BHR phenotype, and the sensitization rate was highest in this group as well.
These children also had decreased lung function and were at an increased risk for newly diagnosed asthma during follow-up (adjusted odds ratio, 3.89). Both early-onset phenotypes were associated with peripheral airway dysfunction. In contrast, children with late-onset BHR phenotypes had an increased risk for allergic rhinitis symptoms at baseline and subsequent sensitization to inhaled allergens.
The authors argued that the diversity among these BHR phenotypes calls for targeted management.
Lee E, Kim Y-H, Cho H-J, et al. Clinical phenotypes of bronchial hyperresponsiveness in school-aged children [published online June 7, 2018]. Ann Allergy Asthma Immunol. doi:10.1016/j.anai.2018.05.033