Definition of asthma in children 1–5 years

Asthma is a chronic inflammatory lung condition, clinically defined as the combination of variable respiratory symptoms (e.g. wheeze, breathlessness, chest tightness, cough) and variable airflow limitation.

‘Asthma’ is a diagnostic label for a group of lung diseases with various disease mechanisms. Multiple asthma phenotypes have been identified, including allergic asthma and nonallergic asthma.

The diagnosis of asthma in children 1–5 years is based on:

• a history of typical symptoms (wheeze, with or without cough) that vary over time in frequency and severity, with acute episodes of breathlessness and/or increased work of breathing
• a low probability that findings are due to an alternative diagnosis
• a rapid clinical response to salbutamol.

Other findings that support the diagnosis of asthma include:

• a clinical response to a treatment trial with ICS, if indicated
• raised fractional exhaled nitric oxide (where testing is available).

The diagnosis of asthma should not be applied to children with intermittent wheezing without increased work of breathing or respiratory distress.