Predicting persistence of asthma in preschool wheezers: crystal balls or muddy waters?

Maybe there is no such thing as bronchiolitis

“…In fact, distinguishing infants with their first and only episode of viral wheezing from those with their first of many subsequent episodes of viral-triggered asthma has been described as "practically impossible." 16 Complicating matters further is the recognition that most exacerbations of preschool asthma are triggered by the same viruses implicated in bronchiolitis. 17 Thankfully, the recognition of different wheezing phenotypes in childhood (Figure 1), based largely on age at presentation and the presence of various risk factors, has been instrumental in providing insight into the heterogeneity of preschool asthma.…”

Diagnosis and management of asthma in preschoolers: A Canadian Thoracic Society and Canadian Paediatric Society position paper

“…Several features are associated with the persistence of asthma at school age, such as the number of wheezing episodes and personal or family history of atopy (as identified in the Asthma Predictive Index [5]), or the age of onset and trajectory of symptoms over time (6); these criteria have slowly become synonymous with the diagnosis of asthma in toddlers, even if this was not the original intention. Moreover, the prediction tools are far from perfect (7,8) and a future trajectory of symptoms cannot be used to make a diagnosis at any age.…”

Altered exhaled biomarker profiles in children during and after rhinovirus-induced wheeze

“…Current symptom-based predictive rules generally have limited accuracy due to heterogeneity of the disease processes underlying LRTS in infancy [7]. Assessing more objective criteria, such as airway hyperresponsiveness, airway obstruction or airway inflammation, is challenging, if not impossible, to perform reliably in preschool children.…”

“…Unfortunately, its predictive value is hampered by the heterogeneity of conditions altering FeNO values [10]. Given the complexity of the histological abnormalities that are already manifest in bronchial biopsies of preschool wheezers [11], composite biomarkers may more robustly reflect the multifactorial pathophysiology of the disease processes underlying wheeze and its potential progression towards asthma [7]. This can be approached by high-throughput "omics" technologies [12].…”