Initial assessment
The assessment of asthma should begin by excluding potentially serious situations. The presence of significant breathlessness, hypoxaemia, marked respiratory distress, altered level of consciousness, a silent chest, cyanosis or suspected severe exacerbation requires urgent assessment and possible referral to hospital.
Clinical suspicion
Once immediate severity has been excluded, the clinical probability of asthma should be assessed. The diagnosis should be suspected in patients with recurrent episodes of wheeze, cough, breathlessness or chest tightness, particularly when symptoms vary over time, worsen at night or are related to physical exercise, respiratory infections, allergens or occupational exposure. A personal or family history of atopy, allergic rhinitis or eczema further supports the diagnosis.
Diagnostic confirmation
The diagnosis of asthma is based on the combination of a compatible clinical history and demonstration of variable expiratory airflow limitation. Spirometry with bronchodilator reversibility testing is the first-line functional investigation. Reversible obstruction, defined by an increase in FEV1 ≥12% and ≥200 mL after bronchodilator administration, supports the diagnosis. However, normal spirometry does not exclude asthma, particularly when performed during an asymptomatic period.
Additional functional assessment
When clinical suspicion remains high but the initial functional assessment is inconclusive, spirometry may need to be repeated during a symptomatic period, PEF variability may be assessed or more advanced functional testing, including bronchial provocation, may be required.
Risk of exacerbation
A modern approach to asthma also includes assessment of the future risk of exacerbations. Previous severe exacerbations, prior hospital admissions, excessive use of SABA, poor treatment adherence, incorrect inhaler technique, smoking, obesity and persistent exposure to environmental or occupational triggers should be identified.
Initial treatment
Assessment of disease severity and control helps guide the treatment strategy. In mild asthma, with occasional symptoms and no relevant risk factors, current recommendations favour strategies containing inhaled corticosteroids from the earliest stages of disease. The preferred treatment includes low-dose ICS-formoterol combinations as needed, reducing the risk of exacerbations associated with the use of short-acting bronchodilators alone. SABA-only treatment is no longer recommended as a routine strategy.
Therapeutic step-up
In persistent or uncontrolled asthma, a therapeutic step-up may be required, with gradual escalation of treatment intensity. Before increasing treatment, adherence, inhaler technique, exposure to triggers and the possible presence of alternative diagnoses or associated comorbidities should be reviewed.
Differential diagnosis and step-down
The main differential diagnoses include COPD, bronchiectasis, heart failure, vocal cord dysfunction and gastro-oesophageal reflux disease. When good clinical control has been sustained, gradual treatment reduction may be considered, aiming for the lowest effective dose that maintains clinical and functional stability.
Severe asthma
In severe or difficult-to-control asthma, referral for specialist assessment should be considered. Some patients may benefit from targeted biological treatment, including anti-IgE, anti-IL5, anti-IL4R or anti-TSLP strategies, selected according to the clinical and inflammatory phenotype.
