Treatment trial in the diagnosis of asthma

A treatment trial of a short-acting beta₂ agonist (SABA) reliever (eg salbutamol, terbutaline) alone or in combination with a regular low-dose inhaled corticosteroid (ICS) preventer can be a useful aid for diagnosis in children 6 years and older, adolescents and adults. Consider a treatment trial in:

patients who cannot perform spirometry
patients in whom the clinical assessment strongly suggests asthma, but initial spirometry does not show airflow limitation.

For information on treatment trials in children aged 1 to 5 years with recurrent bothersome wheeze associated with increased work of breathing, see Treatment trial for wheeze and asthma in children 1 to 5 years.

Instruct patients to use the SABA when they experience acute symptoms. For dosages, see here for adults and adolescents, and here for children 6 years and older. Immediate symptomatic relief of acute asthma symptoms strongly suggests asthma.

A treatment trial with regular low-dose ICS and an as-required SABA can be started in:

patients with significant symptoms or exacerbations who are awaiting spirometry (but spirometry should be done as soon as possible after starting ICS)
patients with significant symptoms or exacerbations who cannot perform spirometry
patients with a strong clinical suspicion of asthma but initial spirometry does not show airflow limitation.

For dosages of regular low-dose ICS, see here for adults and adolescents, and here for children 6 years and older. A clear response (eg improvements in symptoms or lung function) to a trial of ICS therapy of at least 4 weeks supports a diagnosis of asthma.

Note: Consider an alternative diagnosis if symptoms or lung function do not improve with a trial of low-dose ICS for at least 4 weeks.

If treatment trial supports a diagnosis of asthma, start maintenance management of asthma; see here for adults and adolescents, and here for children 6 years and older.