Criteria
Diagnostic criteria for asthma in children aged 0-5 years[1]
International guidelines from the Global Initiative for Asthma (GINA) recommend a probability-based approach plus a trial of treatment for children aged ≤5 years, as most children in this age group cannot perform lung function tests reliably.
Clinical features that would suggest a diagnosis of asthma in children ≤5 years include:
Cough: recurrent or persistent, non-productive cough; may be worse at night; may be associated with wheezing or breathing difficulties; cough may be triggered by exercise, laughing, crying, or exposure to tobacco smoke, especially when a respiratory infection is unlikely
Wheezing: recurrent, may be during sleep, may be triggered by exercise, laughing, crying, exposure to tobacco smoke, or air pollution
Difficult or heavy breathing or shortness of breath: triggered by exercise, laughing, crying
Reduced activity: does not run, play, or laugh at the same intensity as other children; tires more easily when walking/wants to be carried
Past medical history or family history: asthma in first-degree relative; other allergic disease: atopic dermatitis, allergic rhinitis, food allergy
Treatment trial with low-dose inhaled corticosteroid and as-needed short-acting beta agonist (SABA): there is a clinical improvement during 2-3 months of treatment, and deterioration if treatment stops.
Diagnostic criteria for asthma in children aged 6-11 years[1]
According to the GINA guideline, asthma is diagnosed (in people 6 years and above) by identifying a history of respiratory symptoms, such as wheeze, shortness of breath, chest tightness, and cough, that vary over time and in intensity, together with confirmed variable expiratory airflow limitation.
In children ages 6 years and above, GINA recommends confirmation of the asthma diagnosis with a test of variable expiratory airflow limitation. However, please note that variable expiratory airflow limitation is often not present, and spirometry is often normal, in children with mild asthma.
Variable respiratory symptoms
Common symptoms are wheeze, shortness of breath, chest tightness, and cough
Descriptions may vary between cultures and by age
Symptoms vary over time and in intensity
People with asthma generally have more than one type of respiratory symptom
Symptoms are often worse at night, or on waking
Symptoms may be triggered by exercise, laughter, allergens, or cold air
Symptoms may appear or worsen with viral infections
Confirmed variable expiratory airflow limitation
Consists of documented excessive variability in lung function and documented expiratory airflow limitation.
Spirometry measures are used where possible, including the forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and FEV1/FVC ratio.
The peak expiratory flow (PEF) may also be used, but it is considered unreliable in young children and is not recommended for diagnosis. It should not replace spirometry.
At a time when the FEV₁ is reduced, a reduced FEV₁/FVC from spirometry indicates airflow limitation. Children without airflow limitation normally have an FEV₁/FVC ratio of >0.90.
One or more of the following tests confirms excessive variability in lung function. The greater the variations, or the more occasions that excess variation is seen, the more likely is the diagnosis of asthma. Tests can be repeated during symptoms or early in the morning if initially negative. Suggestive test results include:
Positive bronchodilator responsiveness (reversibility) test, as indicated by an increase in FEV₁ of >12% predicted (or PEF of ≥15%) 10-15 minutes after bronchodilator (salbutamol or equivalent); more likely to be positive if bronchodilator medication is withheld before test (SABA ≥4 hours, long-acting beta agonist [LABA] 24-48 hours).
Excessive variability in twice-daily PEF over 2 weeks, as indicated by an average daily diurnal variability in PEF of >13%.
Improved lung function after 4 weeks of treatment, as indicated by an increase from baseline in the FEV₁ of ≥12% predicted, or in the PEF of ≥15%.
Excessive variation in lung function between visits, as indicated by variation in FEV₁ of ≥12% or in the PEF of ≥15%, including respiratory infections; has good specificity but poor sensitivity.
Positive exercise challenge test, as indicated by a fall in FEV₁ of >12% predicted or PEF of >15%.
A guide on how to perform and interpret spirometry, including common pitfalls.
How to use a peak flow meter to obtain a peak expiratory flow measurement.
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