Table 1 Diagnosis of asthma based on medical history, physical examination and objective measurements [4, 6, 7]

Medical history

• Assess for classic symptoms of asthma:

– Wheezing

– Breathlessness

– Chest tightness

– Cough (with our without sputum)

• Assess for symptom patterns suggestive of asthma:

– Recurrent/episodic

– Occur/worsen at night or early in the morning

– Occur/worsen upon exposure to allergens (e.g., animal dander, pollen, dust mites) or irritants (e.g., exercise, cold air, tobacco smoke, infections)

– Respond to appropriate asthma therapy

• Assess for family or personal history of atopic disease (particularly allergic rhinitis)

Physical Examination

• Examine for wheezing on auscultation

• Examine upper respiratory tract and skin for signs of other atopic conditions

Objective Measurements

• Perform spirometry (preferred) to confirm the diagnosis

– Diagnostic criteria:

■ FEV₁ ↑ (after bronchodilator): ≥ 12% and ≥ 200 mL

• Consider PEF as an alternative if spirometry is unavailable

– Diagnostic criteria:

■ PEF ↑ (after bronchodilator): ≥ 20% and 60 L/min

■ Diurnal variation: >20%

• If spirometry (or PEF) is normal, but symptoms are present consider:

– Challenge testing (e.g., methacholine, histamine, mannitol, exercise)

– Non-invasive markers of airway inflammation (exhaled nitric oxide, sputum eosinophilia)

– Trial of appropriate asthma therapy

Allergy testing

• Perform skin tests to assess allergic status and identify possible triggers