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Atopy, bronchial responsiveness, and symptoms in wheezy 3 year olds
N M Wilson1, S B Phagoo, M Silverman
1Department of Paediatrics and Neonatal Medicine, Royal Postgraduate Medical School, Hammersmith Hospital, London.
Insights
In young children, non-atopic infants showed higher bronchial responsiveness compared to atopic ones. Wheezing associated with colds in early childhood appears unrelated to atopy.
Area of Science:
- Pediatric Pulmonology
- Allergy and Immunology
- Respiratory Medicine
Background:
- Acute lower airway obstruction in infancy is a common pediatric concern.
- Understanding the interplay between atopy, bronchial responsiveness, and symptom patterns is crucial for early diagnosis and management.
- Previous research often focused on older children and adults, leaving a gap in knowledge for very young children.
Purpose of the Study:
- To investigate the relationship between atopy, bronchial responsiveness, and symptom patterns in children with a history of acute lower airway obstruction.
- To determine if bronchial responsiveness differs between atopic and non-atopic children in early life.
- To explore the association between symptom patterns (e.g., wheeze with colds) and atopic status.
Main Methods:
- Assessment of 50 children at 3 years of age with prior hospital admissions for acute lower airway obstruction.
- Measurement of bronchial responsiveness using inhaled methacholine challenge, with transcutaneous oxygen tension (PtCO2) as an indirect response indicator.
- Classification of symptom patterns based on wheezing episodes related to colds and non-viral cough/wheeze, alongside atopy assessment via skin prick tests or history.
Main Results:
- Forty percent of the children were identified as atopic.
- Non-atopic children exhibited significantly greater bronchial responsiveness (lower methacholine PC20) than atopic children.
- Onset of respiratory symptoms in the first year of life was more common in non-atopic children; atopic children more frequently had cough/wheeze unrelated to colds and used continuous medication.
- The frequency of acute wheezing episodes associated with colds was similar in both atopic and non-atopic groups.
Conclusions:
- In this cohort, acute wheezing associated with colds during the first three years of life appears independent of atopy.
- Bronchial responsiveness in this young age group may stem from different mechanisms than in older individuals.
- These findings suggest distinct pathways for early-life wheeze and highlight the need for age-specific diagnostic and therapeutic approaches.
Abstract:
Fifty children with at least one hospital admission for acute lower airway obstruction in the first 2.5 years of life were assessed at 3 years of age to determine the relationship between atopy, bronchial responsiveness, and the pattern of their symptoms. Bronchial responsiveness was measured by assessing the effect of inhaled metacholine, using the change in transcutaneous oxygen tension (PtCO2) as an indirect measure of response. Symptom patterns were defined by the number of wheezing episodes associated with colds and the presence or absence of cough or wheeze unrelated to viral infections. Forty per cent of the children were found to be atopic by skin prick test or history. In contrast to the situation found in older children and adults, the non-atopic children had significantly greater bronchial responsiveness (lower mean concentration of methacholine causing a 20% fall in PtCO2, the PC20) than the atopic children and significantly more of them had an onset of respiratory symptoms in the first year of life. Cough and wheeze in the absence of colds was more frequently found in the atopic children as was the use of continuous medication. However, the number of reported acute episodes of wheeze associated with colds was the same in the two groups. The findings of the study suggest that in this hospital based group of children, acute wheeze associated with colds in the first three years of life is independent of the finding of atopy and that bronchial responsiveness in this age group may have a different pathogenesis from that in older subjects.