Which of the following findings indicates asthma: (A) polyphonic wheezing with exercise, (B) normal chest radiograph between episodes, (C) family history of asthma?

Which Finding Most Indicates Asthma?

Polyphonic wheezing with exercise (Option A) is the strongest indicator of asthma among these three options, as it directly demonstrates the pathophysiologic hallmark of reversible airway hyperresponsiveness triggered by a characteristic precipitant. 1, 2

Why Exercise-Induced Polyphonic Wheezing is Diagnostic

Exercise-induced bronchospasm represents a highly specific clinical measure that directly demonstrates reversible airway hyperresponsiveness—the defining pathophysiologic feature of asthma. 1 The British Thoracic Society explicitly identifies symptoms provoked by triggers such as exercise as a defining hallmark of asthma diagnosis. 1

Key Diagnostic Features:

• Polyphonic wheeze (diffuse, bilateral, especially expiratory) is a cardinal sign of asthma and should be documented when present 1, 2
• Trigger-provoked symptoms (especially exercise) combined with wheezing constitute core diagnostic criteria 1
• Recurrent wheezing episodes that occur with typical precipitants like exercise and are relieved by β-adrenergic agents meet established diagnostic criteria 1

Why Normal Chest X-Ray Between Episodes (Option B) Does NOT Indicate Asthma

A normal chest radiograph between episodes is expected in asthma but provides no diagnostic value. 1, 2

• Chest radiography is performed only to exclude alternative diagnoses, not as a diagnostic criterion for asthma 1, 2
• Physical examination and objective signs (including radiographic abnormalities) may be completely absent between acute exacerbations 1, 3
• Normal imaging does not increase or decrease the likelihood of asthma diagnosis 1

Common pitfall: Clinicians sometimes mistakenly believe that normal chest X-rays "support" asthma diagnosis, when in reality they are simply non-contributory. 2

Why Family History of Asthma (Option C) Does NOT Indicate Asthma

Family history of atopy is the most important recognized risk factor for atopic disease in children, yet it does not confirm an asthma diagnosis on its own. 1

• The British Thoracic Society considers family history as additional contextual information that may raise clinical suspicion rather than a diagnostic criterion 1
• The European Respiratory Society explicitly states that diagnosis should not be based on family history without documenting variable airflow obstruction or characteristic symptom patterns like exercise-induced bronchospasm 1
• Relying on family history alone results in misdiagnosis in a considerable number of children 1

Comprehensive Diagnostic Approach

No single test definitively diagnoses asthma; diagnosis requires integration of typical trigger-related symptoms (especially exercise-provoked), objective evidence of airflow limitation when obtainable, and documented response to asthma pharmacotherapy. 1

The Diagnostic Algorithm:

1. Document characteristic symptom patterns: wheezing, shortness of breath, chest tightness, or cough that are variable, intermittent, and trigger-provoked 2
2. Obtain objective confirmation: Spirometry demonstrating reversible airflow obstruction (FEV1 improvement ≥12% and ≥200 mL after bronchodilator) in patients 5 years and older 2
3. Consider bronchoprovocation testing: When spirometry is normal but clinical suspicion remains high based on exercise-induced symptoms 2, 4

Critical caveat: While exercise-induced polyphonic wheezing is highly suggestive, definitive diagnosis requires objective confirmation through airway reversibility testing or exercise challenge, as self-reported symptoms alone can lead to misdiagnosis. 1