Synopsis
Confirm asthma with variable symptoms plus objective evidence, recognise dangerous mimics and work-related disease, and use phenotype information to guide referral without replacing the core diagnosis.
- Asthma is a clinical syndrome of variable respiratory symptoms and variable expiratory airflow limitation; neither symptoms nor a single test is sufficient in every patient.
- Typical variability includes episodic wheeze, breathlessness, chest tightness or cough that changes over time and with triggers, nights, seasons, work or treatment.
- Before testing, document recent inhaled corticosteroid because it can suppress eosinophils, FeNO and reversibility and make objective confirmation harder.
Key red flags
Asthma with chronic rhinosinusitis/nasal polyps and reproducible respiratory reactions to aspirin or other COX-1 NSAIDs. Avoid unsupervised challenge and refer when diagnosis or analgesic options are uncertain.
Investigation priorities
Estimate pre-test probability and identify urgency, triggers, risk and alternatives.
Management branches
History suggests asthma and the person is not acutely unstable.
- 1. Record symptoms, examination, exposures, treatment and alternatives; do not confirm asthma on symptoms alone.
- 2. Measure blood eosinophils or FeNO. In a compatible presentation, eosinophils above the laboratory range or FeNO at least 50 ppb can confirm asthma.
Key medicines
Budesonide/formoterol anti-inflammatory reliever after diagnosisExample licensed product: budesonide/formoterol delivered 160/4.5 micrograms, 1 inhalation as needed; if symptoms persist take 1 further inhalation. Not more than 6 on one occasion; more than 8/day is not normally needed and up to 12/day is only for a limited period under the product directions.
Salbutamol for reversibility testing400 micrograms inhaled through a spacer for diagnostic bronchodilator reversibility, with repeat spirometry after the protocol interval.