This Guidelines summary is taken from the GINA 2020 pocket guide for asthma management and prevention. It outlines recommendations for making the diagnosis of asthma in adults and children over five years of age.
This summary includes information on:
- making the initial diagnosis
- confirming the diagnosis in patients taking controller treatment
- diagnosing asthma in other contexts.
Refer to the full GINA 2020 Global strategy for asthma management and prevention report for information on:
- patterns of respiratory symptoms that are characteristic of asthma
- physical examination
- lung function testing to document variable expiratory airflow limitation
- confirming a diagnosis of asthma in obese patients.
Download the full global strategy for asthma management and prevention:
NB: When assessing and treating patients, health professionals are strongly advised to use their own professional judgement and to take into account local and national regulations and guidelines.
View the full group of Guidelines GINA asthma strategy summaries at guidelines.co.uk/ginaasthma.
Making the initial diagnosis
Asthma is a disease with many variations (phenotypes), usually characterised by chronic airway inflammation. Asthma has two key defining features:
- a history of respiratory symptoms such as wheeze, shortness of breath, chest tightness and cough that vary over time and in intensity, AND
- variable expiratory airflow limitation.
A flowchart for making the diagnosis in clinical practice is shown in Algorithm 1, with the specific criteria for diagnosing asthma in Table 1.
Algorithm 1: Diagnostic flowchart for clinical practice—initial presentation
Criteria for making the diagnosis of asthma
Table 1: Features used in making the diagnosis of asthma
1. A history of variable respiratory syndromes
Typical symptoms are wheeze, shortness of breath, chest tightness, cough:
2. Evidence of variable expiratory airflow limitation
[A] Using Global Lung Initiative multi-ethnic reference equations.
[B] Calculated from twice daily readings (best of three each time), as (the day’s highest PEF minus the day’s lowest PEF) divided by the mean of the day’s highest and lowest PEF, and averaged over one to two weeks. If using PEF at home or in the office, use the same PEF meter each time.
Physical examination in people with asthma is often normal, but the most frequent finding is wheezing on auscultation, especially on forced expiration.
How to confirm the diagnosis in patients taking controller treatment
For many patients (25–35%) with a diagnosis of asthma in primary care, the diagnosis cannot be confirmed. If the basis of the diagnosis has not already been documented, it should be confirmed with objective testing.
If standard criteria for asthma (Table 1) are not met, consider other investigations. For example, if lung function is normal, repeat reversibility testing when the patient is symptomatic, or after withholding SABA for >4 hours, twice-daily ICS-LABAs for >12 hours, and once-daily ICS+LABAs for >24 hours. If the patient has frequent symptoms, consider a trial of step-up in controller treatment and repeat lung function testing after three months.
If the patient has few symptoms, consider stepping down controller treatment; ensure the patient has a written asthma action plan, monitor them carefully, and repeat lung function testing.
More information about confirming the diagnosis of asthma is in Boxes 1-3 and 1-4 of the full GINA 2020 report.
Diagnosis of asthma in other contexts
Occupational asthma and work-aggravated (work-exacerbated) asthma
Every patient with adult-onset asthma should be asked about occupational exposures, and whether their asthma is better when they are away from work. It is important to confirm the diagnosis objectively (which often needs specialist referral) and to eliminate exposure as quickly as possible.
Ask all pregnant women and those planning pregnancy whether they have asthma, and advise them about the importance of taking asthma controller treatment for the health of both mother and baby.
Asthma may be under-diagnosed in the elderly, due to poor perception, an assumption that dyspnoea is normal in old age, lack of fitness, or reduced activity. Asthma may also be over-diagnosed in the elderly if shortness of breath due to heart failure or ischemic heart disease is mistakenly attributed to asthma. If there is a history of smoking or biomass fuel exposure, COPD or asthma-COPD overlap should also be considered.
Smokers and ex-smokers
Asthma and COPD may co-exist or overlap (sometimes called asthma-COPD overlap [ACO] or asthma+COPD), particularly in smokers and the elderly. The history and pattern of symptoms and past records can help to distinguish asthma with persistent airflow limitation from COPD. Uncertainty in diagnosis should prompt early referral, because asthma-COPD overlap has worse outcomes than asthma or COPD alone. Asthma-COPD overlap is not a single disease, but is likely caused by several different mechanisms.
There is little randomised controlled trial evidence about how to treat these patients, as they are often excluded from clinical trials. However, patients with a diagnosis of COPD who also have any history or diagnosis of asthma should be treated as for asthma, including at least low dose ICS (see Box 9 on low, medium and high daily doses of inhaled corticosteroids in the pocket guide), because of the risks associated with treating asthma with bronchodilators alone.
Patients with persistent cough as the only respiratory symptom
This may be due to chronic upper airway cough syndrome (‘post-nasal drip’), chronic sinusitis, gastro-oesophageal reflux disease (GORD), inducible laryngeal obstruction (often called vocal cord dysfunction), eosinophilic bronchitis, or cough variant asthma. Cough variant asthma is characterised by cough and airway hyperresponsiveness, and documenting variability in lung function is essential to make this diagnosis. However, lack of variability at the time of testing does not exclude asthma.
For other diagnostic tests, see Box 2, and Chapter 1 of the full GINA report, or refer the patient for specialist opinion.
Global Initiative for Asthma. Global strategy for asthma management and prevention—updated 2020. April 2020. www.ginaasthma.org
Published date: 1995.
Last updated: April 2020.
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