#### Summary points Lower respiratory tract illnesses with wheeze are common, occurring in around a third of all preschool children (here defined as aged between 1 and 5 years). They are a major source of morbidity and healthcare costs, including time off work for carers, and are often difficult to treat. This review focuses on the two areas in which there have been recent developments. The first is the classification of these children by symptom pattern into “episodic viral” and “multiple trigger” wheezers.1 These phenotypes can change within an individual over time,2 but they are a useful guide to current treatment, and there are also physiological and pathological rationales for their use.3 4 The second area is the recent series of large randomised controlled trials of treatment, specifically related to the roles of intermittent montelukast and inhaled and oral corticosteroids. These trials have shown clearly that inhaled corticosteroids and prednisolone in particular have been misused and overused in the past, mandating a reappraisal of treatment algorithms. Video abstract #### Sources and selection criteria We performed a …