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

FVC: forced vital capacity; FEV₁: forced expiratory volume in 1 second; PEF: peak expiratory flow