Asthma Diagnosis and Management

Diagnostic Testing

• The European Respiratory Society strongly recommends pulmonary function testing, including spirometry with bronchodilator reversibility (BDR) testing, as a first-line diagnostic test for adolescents with asthma aged 5-16 years, requiring at least two objective test results to confirm diagnosis, with abnormal results defined as FEV1 or FEV1/FVC less than lower limit of normal and/or <80% predicted, and BDR positive if ≥12% and/or ≥200 mL improvement after bronchodilator 1
• Peak Expiratory Flow Rate (PEFR) Variability measured over 2 weeks with twice-daily measurements can be used as an alternative diagnostic test, with variability ≥12% considered significant, but is less reliable than spirometry and BDR 1
• Exhaled Nitric Oxide Fraction (FeNO) measurement is recommended, with a cut-off of 25 ppb, and should ideally be performed before spirometry, as suggested by the Global Initiative for Asthma (GINA) 1
• Challenge testing, including direct bronchial challenge with methacholine or indirect testing using exercise, is recommended when other tests fail to confirm diagnosis, as suggested by the European Respiratory Society 1
• The following table summarizes the diagnostic algorithm for asthma in children:

1

Diagnostic Considerations

• Recurrent wheeze is the most important symptom for diagnosis, with a sensitivity of 0.55-0.86 and specificity of 0.64-0.90, and frequency of symptoms, including >3 episodes of wheezing in past year lasting >1 day and affecting sleep, with a strength of evidence level of high, as suggested by the American Academy of Pediatrics 2
• A thorough symptom history, including pattern, frequency, and severity of wheeze, cough, and breathing difficulty, as well as triggers and response to previous treatments, is essential for diagnosing asthma in children under 5 years, as recommended by pediatric guidelines 1
• Risk factors for persistent asthma, including parental history of asthma, diagnosed allergic rhinitis, peripheral blood eosinophilia, and wheezing apart from colds, should be considered, with a strength of evidence level of moderate, as recommended by the American Academy of Allergy, Asthma, and Immunology 2
• Alternative diagnoses, including foreign body aspiration, congenital airway abnormalities, cystic fibrosis, primary immunodeficiency, vascular ring, and tracheomalacia, should be considered, with a strength of evidence level of moderate, as recommended by the European Respiratory Society 2

Monitoring and Assessment

• The Global Initiative for Asthma (GINA) report emphasizes that objective lung function measurements are necessary for confirming asthma diagnosis and continued monitoring, with regular monitoring of lung function recommended to assess response to treatment, detect early deterioration, and identify potential exacerbation triggers 3, 1
• A "trial of preventer medication" is not sufficient as a diagnostic test without objective improvement in lung function, as recommended by the European Respiratory Society 1
• The European Respiratory Society recommends at least two abnormal objective test results for diagnosis in children 5 years and older, with a strength of evidence level of high 1

Special Considerations

• Diagnosing asthma in children under 5 years is challenging due to the inability to perform reliable spirometry and difficulty distinguishing from viral-induced wheezing, with a strength of evidence level of low, as suggested by the American Academy of Allergy, Asthma, and Immunology 2
• A therapeutic trial of asthma medication with careful monitoring of response may be appropriate in young children where objective testing is not feasible, as suggested by clinical practice 1
• Salbutamol (albuterol) syrup can be used for short-term symptomatic relief in viral wheeze, but should not be used as a diagnostic tool alone and is not recommended for long-term management of viral wheeze, with a strength of evidence level of moderate, as recommended by the European Respiratory Society 1
• Response to bronchodilators in viral wheeze may be variable and does not confirm asthma diagnosis, and regular use is not recommended for viral-induced wheeze without confirmed asthma, with a strength of evidence level of low, as suggested by the American Academy of Allergy, Asthma, and Immunology 2