Wheezing in Children Under Five Years: A Narrative Review

Background: Wheezing in preschool children is a common and heterogeneous clinical problem that poses significant diagnostic and therapeutic challenges. Symptom-based phenotypes have traditionally guided management, but their ability to reflect underlying mechanisms and predict treatment response is limited. Methods: This narrative review summarises current understanding based on recent evidence in the diagnosis and management of preschool wheezing. It is intended for paediatricians who routinely manage children with recurrent wheezing. Results: Preschool wheezing affects approximately 50% of children during the first 6 years of life, with distinct trajectories. Over the past two decades, accumulating evidence suggests that symptom-based phenotyping alone is insufficient to reliably guide treatment decisions. Children with recurrent or severe wheezing episodes should undergo evaluation for any underlying secondary causes before applying the GINA 2025 criteria for diagnosis of asthma. Objective biomarkers related to type 2 inflammation, such as eosinophilia and allergic sensitisation, help identify children likely to benefit from inhaled steroids. Conclusion: Preschool wheezing represents a spectrum of disorders. A shift toward biomarkers-driven approaches may improve precision in management of these children and further research is required for improving outcomes.