Diagnosing asthma in children
A clinical definition of asthma in children
Asthma is defined clinically as the combination of variable respiratory symptoms (e.g. wheeze, shortness of breath, cough and chest tightness) and excessive variation in lung function, i.e. variation in expiratory airflow that is greater than that seen in healthy children (‘variable airflow limitation’).
There is no single reliable test (‘gold standard’) and there are no standardised diagnostic criteria for asthma.
The diagnosis of asthma is based on:
- physical examination
- considering other diagnoses
- clinical response to a treatment trial with an inhaled short-acting beta2 agonist reliever or preventer
Figure: Steps in the diagnosis of asthma in children aged 1-5 years Please view and print this figure separately: http://www.asthmahandbook.org.au/figure/show/17
Figure. Steps in the diagnosis of asthma in children aged 6 years and over Please view and print this figure separately: http://www.asthmahandbook.org.au/figure/show/121
Infants (age 0–12 months)
Asthma should not be diagnosed in infants aged less than 12 months old. Wheezing in this age group is most commonly due to acute viral bronchiolitis or to small and/or floppy airways. Infants with clinically significant wheezing should be referred to a paediatric respiratory physician or paediatrician.
Preschool wheeze (age 1–5 years)
Although many individuals later diagnosed with asthma first show respiratory symptoms by the age of 5 years, it is difficult to make the diagnosis of asthma with a high degree of certainty in children aged 1–5 years, because:
- episodic respiratory symptoms such as wheezing and cough are very common in children, particularly in children under 3 years
- objective lung function testing by spirometry is usually not feasible in this age group
- a high proportion of children who respond to bronchodilator treatment do not go on to have asthma in later childhood (e.g. by primary school age).
Children aged 6–11 years
In school-aged children able to perform spirometry, the diagnosis is supported by documentation of variable expiratory airflow limitation.
In older adolescents, the guidance on the diagnosis of asthma in adults generally applies.
In this section
Diagnosis: ages 1–5
Investigating wheeze and other asthma symptoms in preschool children, including history and physical examination, differential diagnosis, further investigations and treatment trials
Diagnosis: age 6 and over
Investigating asthma symptoms in school-aged children, including history and physical examination, spirometry, differential diagnosis, further investigations and treatment trials