From the Guidelines
Asthma diagnosis in adults is established by the presence of episodic symptoms of airflow obstruction or airway hyperresponsiveness, at least partially reversible airflow obstruction, and the exclusion of alternative diagnoses.
Diagnostic Criteria
The diagnostic criteria for adult asthma include:
- Episodic symptoms of airflow obstruction or airway hyperresponsiveness, such as:
- Cough (worse particularly at night)
- Recurrent wheeze
- Recurrent difficulty in breathing
- Recurrent chest tightness
- Airflow obstruction that is at least partially reversible, measured by spirometry, with an increase in FEV1 of >200 mL and 12% from baseline after inhalation of a short-acting β2-agonist (SABA) 1
- Symptoms that occur or worsen in the presence of specific triggers, such as:
- Exercise
- Viral infection
- Inhalant allergens (e.g., animals with fur or hair, house-dust mites, mold, pollen)
- Irritants (tobacco or wood smoke, airborne chemicals)
- Changes in weather
- Strong emotional expression (laughing or crying hard)
- Stress
- Menstrual cycles
Diagnostic Methods
Recommended methods to establish the diagnosis of asthma include:
- Detailed medical history, focusing on the overall pattern of symptoms, precipitating factors, and family history of asthma, allergy, or other atopic disorders 1
- Physical examination, focusing on the upper respiratory tract, chest, and skin
- Spirometry, which is an essential objective measure to establish the diagnosis of asthma, as it can demonstrate obstruction and assess reversibility in patients aged 5 years or older 1
Differential Diagnosis
A differential diagnosis of asthma should be considered, including:
- COPD (e.g., chronic bronchitis or emphysema)
- Congestive heart failure
- Pulmonary embolism
- Mechanical obstruction of the airways (benign and malignant tumors)
- Pulmonary infiltration with eosinophilia
- Cough secondary to drugs (e.g., angiotensin-converting enzyme inhibitors)
- Vocal cord dysfunction (VCD) 1 Additional studies, such as chest x-ray, specific blood tests, or bronchoprovocation with methacholine, histamine, cold air, or exercise challenge, may be useful in excluding alternative diagnoses or identifying other potential causes of symptoms 1
From the Research
Diagnostic Criteria for Adult Asthma
The diagnostic criteria for adult asthma involve a combination of clinical symptoms and objective tests of lung function. The key diagnostic criteria include:
- Presence of typical symptoms such as cough, wheeze, breathlessness, and chest tightness 2
- Demonstration of airway obstruction using spirometry 3, 4, 5
- Documentation of variability in degree of obstruction using tests such as bronchodilator reversibility, peak expiratory flow variability, or bronchial challenge testing 3, 4, 6
- Measurement of fractional exhaled nitric oxide to support a diagnosis of atopic asthma 4, 6
Diagnostic Tests
The following diagnostic tests are used to diagnose asthma in adults:
- Spirometry with bronchodilator reversibility testing: considered the mainstay of asthma diagnostic testing 3, 4, 5
- Peak expiratory flow variability: a simple test to implement in a clinical and home setting 4
- Bronchial challenge testing: reserved for patients with unrevealing initial testing but high clinical suspicion 4, 6
- Fractional exhaled nitric oxide measurement: supportive of atopic asthma, but with limited diagnostic utility in non-atopic asthma 4, 6
Guideline Recommendations
Different guidelines have been established for the diagnosis of asthma in adults, including:
- European Respiratory Society (ERS) guidelines: recommend spirometry followed by bronchodilator reversibility testing, and further tests such as exhaled nitric oxide fraction or peak expiratory flow variability if initial spirometry is normal 3
- National Institute for Health and Care Excellence (NICE) guidelines: provide excellent specificity but low sensitivity 6
- Global Initiative for Asthma (GINA) guidelines: provide excellent specificity but low sensitivity 6
- Comparison of guidelines: shows moderate concordance between guidelines, highlighting the need for new guidelines that can be tested prospectively 6