Clinical manifestations and consequences
As previously discussed, asthma often starts in early childhood with acute attacks or exacerbations provoked by respiratory viral infections. Attention has focused on different asthma phenotypes especially during infancy and pre-school age, with diagnostic labels such as early wheeze, transient wheeze and late-onset wheeze, describing the longitudinal outcome of wheezing during early childhood. However, such retrospective labelling is not useful in predicting the prognosis. Recurrent wheezing during pre-school years often improves during school years and puberty. However, longitudinal cohort studies show that respiratory symptoms and bronchial obstruction often recur after the age of 16–20 years.
Most cases of asthma during childhood are mild or moderate and can be optimally controlled with treatment. However, a proportion have severe problematic asthma even during childhood, with lack of response to treatment with inhaled corticosteroids.
Exercise-induced asthma is particularly common in children and, if untreated, it may reduce activity and impair fitness. A major goal of all international guidelines for treating childhood asthma is to master exercise-induced asthma.