From the Guidelines
A diagnosis of asthma should be considered when a patient presents with episodic symptoms of airflow obstruction or airway hyperresponsiveness, and airflow obstruction is at least partially reversible, as measured by spirometry, with an increase in FEV1 of >200 mL and 12% from baseline after inhalation of a short-acting b2-agonist (SABA) 1. To establish a diagnosis of asthma, the following key symptom indicators should be present:
- Episodic symptoms of airflow obstruction or airway hyperresponsiveness
- Airflow obstruction is at least partially reversible, measured by spirometry
- History of symptoms such as cough, recurrent wheeze, recurrent difficulty in breathing, and recurrent chest tightness
- Symptoms occur or worsen in the presence of triggers such as exercise, viral infection, inhalant allergens, irritants, changes in weather, strong emotional expression, stress, menstrual cycles, and at night The diagnosis of asthma involves a comprehensive evaluation of symptoms, medical history, and lung function tests, including:
- Detailed medical history
- Physical examination
- Spirometry to demonstrate obstruction and assess reversibility
- Peak flow monitoring for ongoing management, rather than diagnosis It is essential to consider a differential diagnosis of asthma, as recurrent episodes of cough and wheezing can be caused by other conditions, and additional tests such as chest X-rays, CT scans, and blood tests may be ordered to rule out other conditions 1.
From the Research
Diagnostic Criteria for Asthma
- Asthma diagnosis is based on the combined presence of typical symptoms and objective tests of lung function 2, 3
- Diagnostic tests can only increase or decrease the probability of the asthma diagnosis, so a thorough history is very important 2
- Spirometric evidence of airway obstruction plus a large bronchodilator response makes asthma much more likely 2
Objective Diagnostic Testing
- Spirometry with bronchodilator reversibility testing remains the mainstay of asthma diagnostic testing for children and adults 3
- Repetition of the test over several time points may be necessary to confirm airway obstruction and variability thereof 3
- Repeated peak flow measurement is relatively simple to implement in a clinical and home setting 3
- Bronchial challenge testing is reserved for patients in whom the aforementioned testing has been unrevealing but clinical suspicion remains 3
Differential Diagnosis
- Adult smokers with intermittent respiratory symptoms may have either asthma or chronic obstructive pulmonary disease (COPD) 2
- Normal post-bronchodilator spirometry rules out COPD 2
- A low diffusing capacity of the lung for carbon monoxide increases the probability of COPD and makes asthma much less likely 2
- A high exhaled nitric oxide level makes allergic asthma more likely 2
Treatment and Management
- Response to inhaled corticosteroids makes asthma more likely and COPD less likely 2
- Treatment with fluticasone furoate/vilanterol, an inhaled corticosteroid/long-acting β2-agonist therapy, reduces the risk of severe asthma exacerbations and improves lung function and symptom control in patients with asthma 4
- Inhaled corticosteroids (ICSs) and long-acting inhaled beta(2)-agonists (LABAs) are recommended treatment options for asthma 5