Episodic viral wheeze and multiple trigger wheeze in preschool children: a useful distinction for clinicians?

Area of Science:

• Pediatric Pulmonology
• Allergy and Immunology
• Respiratory Medicine

Background:

• Current classification of preschool recurrent wheezing into Episodic (Viral) Wheeze (EVW) and Multiple Trigger Wheeze (MTW) lacks robust evidence.
• There is limited data supporting distinct longitudinal patterns or underlying pathologies for EVW and MTW phenotypes.
• Clinical responses to common asthma medications vary significantly within these proposed phenotypes, questioning their clinical utility.

Purpose of the Study:

• To evaluate the current EVW-MTW classification system for preschool recurrent wheezing.
• To propose an improved framework for describing preschool wheeze based on clinical parameters.
• To guide future research towards identifying phenotypes with distinct pathobiological processes and treatment responses.

Main Methods:

• Review of accumulating evidence on preschool recurrent wheezing phenotypes.
• Analysis of clinical response variability to inhaled corticosteroids and montelukast.
• Proposal for a revised descriptive approach for preschool wheeze symptoms.

Main Results:

• The EVW-MTW classification is likely an oversimplification with doubtful clinical usefulness.
• Evidence linking these phenotypes to distinct longitudinal wheeze patterns or pathologies is scarce.
• Significant inter-individual variability in treatment response exists within proposed EVW and MTW groups.

Conclusions:

• A revised approach to describing preschool wheeze, incorporating temporal pattern, frequency, severity, and age of onset, is proposed.
• Associated clinical parameters like atopy and eczema should be detailed considering age, pattern, and severity.
• Further research correlating clinical data with biomarkers and histopathology is needed to refine understanding and treatment of preschool wheezing disorders.