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Definition of pediatric asthma and associated risk factors
1Department of Pediatrics, University of Arizona, Tucson, USA.
Insights
Childhood asthma presents in two main ways: transient wheezing often linked to narrower airways, and persistent wheezing associated with immune responses typical of asthma. Identifying these distinct patterns is key for effective treatment.
Area of Science:
- Pediatric Pulmonology
- Immunology
- Respiratory Medicine
Background:
- Childhood asthma exhibits diverse phenotypes, complicating diagnosis and treatment.
- Wheezing during early childhood viral infections is common but may not indicate persistent asthma.
Purpose of the Study:
- To differentiate between transient and persistent wheezing phenotypes in young children.
- To identify distinct characteristics and risk factors associated with each wheezing phenotype.
- To explore the role of immune responses and airway structure in childhood asthma development.
Main Methods:
- Analysis of wheezing patterns in children during the first three years of life.
- Assessment of risk factors including serum IgE levels, bronchial hyperresponsiveness, and family history.
- Evaluation of lung function and immune responses (e.g., T-helper 2 cell predominance) to viral infections.
Main Results:
- A significant group (20%) experiences transient wheezing linked to narrower airways, with symptoms resolving by age three and lacking typical asthma risk factors.
- Another group (10%) exhibits persistent wheezing, presenting with established asthma risk factors and a T-helper 2-like immune response to viruses.
- Reduced lung function is an early indicator in children with transient wheezing, preceding illness onset.
Conclusions:
- Two distinct phenotypes of early childhood asthma exist: one characterized by transient wheezing and narrower airways, the other by persistent symptoms and an asthma-associated immune profile.
- Understanding these differences and developing prognostic tests are crucial for targeted prevention and treatment strategies.
- Early identification of these phenotypes may guide interventions to improve long-term respiratory health outcomes in children.
Abstract:
Significant advances have been made in recent years in understanding the different ways in which asthma is expressed during childhood. There is a large group of children (20% of the population) who present with wheezing during viral infections during the first 3 years of life but whose symptoms disappear after this age. These children do not have any of the important risk factors associated with asthma in later childhood (high serum IgE levels, bronchial hyperresponsiveness, family history of asthma). The main characteristic associated with this condition is reduced lung function, which can be detected before these illnesses develop. It has been suggested that there is nothing unusual or characteristic in the immune response to viruses in these children, but it would appear that these children have narrower intrapulmonary airways. A second group of young children (10% of the population), who also wheeze during viral infections, present with most of the risk factors associated with asthma in later childhood. In this group of children symptoms tend to persist with age. It appears that in these children the immune response to viruses is characterized by a predominance of TH2-like cells. This suggests that their early wheezing is the expression of asthma because a TH2-like response to allergens and viruses is a characteristic found in most asthmatic children. A better understanding of the different types of childhood asthma, together with development of accurate prognostic tests, may be decisive in determining adequate strategies for prevention and treatment of the condition.