Most Appropriate Next Investigation for Child with Eczema, Cough, and Wheezing Post-URTI
For this child with eczema presenting with cough and wheezing following a URTI, spirometry with bronchodilator response testing (if age-appropriate) combined with chest X-ray is the most appropriate next investigation. 1, 2
Clinical Context and Diagnostic Approach
This clinical presentation strongly suggests asthma given the combination of:
- History of atopic dermatitis (eczema) - which places the child at high risk for developing asthma through the "allergic march" 1
- Recurrent episodes of cough and wheezing - the most important symptom constellation for asthma 2, 3
- Post-viral trigger pattern - consistent with asthma exacerbations 1
The presence of eczema plus wheezing is particularly significant, as children with early childhood eczema have a 34.1% risk of developing asthma, and this combination places them at high risk for persistent asthma throughout childhood 1, 3.
Recommended Initial Investigations
Primary Tests (Both Should Be Performed)
1. Chest X-ray 1
- Recommended as minimum baseline investigation for all children with chronic or recurrent respiratory symptoms
- Excludes structural abnormalities, pneumonia, or other pathology
- Grade 1B recommendation from CHEST guidelines 1
2. Spirometry with Bronchodilator Response Testing (if age-appropriate, typically ≥5 years) 1, 2, 3
- First-line objective test for children aged 5-16 years under investigation for asthma 2, 3
- Most children in this age range can successfully perform acceptable spirometry 2, 4
- Bronchodilator reversibility showing ≥12% improvement in FEV1 is a key diagnostic criterion for asthma 2, 3
- Grade 1B recommendation from CHEST guidelines 1
Critical Diagnostic Principles
Asthma should NOT be diagnosed on symptoms alone, even with classic features like recurrent wheeze and atopy present 2, 3. The European Respiratory Society strongly emphasizes that at least two abnormal objective tests are required for asthma diagnosis 2, 3.
Important Timing Consideration
Testing is most useful when the child is symptomatic or when wheezing is present on examination, as lung function tests are frequently normal during stable disease 2, 3. If the child is currently asymptomatic, consider scheduling testing during symptomatic periods.
Why Other Options Are Less Appropriate
CT scan of the chest (Option C) - Not routinely recommended as initial investigation 1. CHEST guidelines specifically recommend against routinely performing CT scans; these should be individualized and undertaken only when specific clinical indicators suggest structural abnormalities, bronchiectasis, or when initial investigations are inconclusive 1.
Bronchoscopy (Option D) - Reserved for specific indications 1:
- Persistent wheezing despite appropriate treatment with bronchodilators and corticosteroids 1
- Suspicion of anatomic abnormalities 1
- Chronic wet/productive cough with specific cough pointers 1
- Not indicated as first-line investigation for typical asthma presentation
Antihistamine therapy - Not appropriate as a diagnostic investigation. While this child has atopic history, the primary concern is lower airway disease (wheezing), not allergic rhinitis alone 1.
Additional Diagnostic Considerations
If spirometry and bronchodilator testing are performed, consider fractional exhaled nitric oxide (FeNO) testing as a second objective test, as elevated levels suggest eosinophilic airway inflammation 2, 3.
Age-Specific Modifications
If the child is under 5 years old and cannot perform spirometry 2, 3:
- Chest X-ray remains essential 1
- Diagnosis becomes more challenging without objective lung function measurements 5
- A carefully monitored therapeutic trial may be appropriate, but this requires clear-cut response criteria: improvement with moderate-dose inhaled corticosteroids, relapse upon stopping, and second response to recommencing treatment 5
Common Pitfalls to Avoid
Do NOT assume cough alone represents asthma - children with chronic cough as the only symptom are unlikely to have asthma and should be investigated according to chronic cough guidelines 2, 5. However, this child has both cough AND wheezing, making asthma much more likely 2.
Do NOT start empiric inhaled corticosteroids without objective confirmation 2, 5. Symptom improvement after treatment alone should not be used to diagnose asthma 2, 3.
Do NOT use vague labels like "reactive airway disease" or "wheezy bronchitis" to avoid proper diagnostic evaluation 5.
Assessment for Comorbidities
Given the atopic history, also assess for associated conditions including allergic rhinitis, allergic conjunctivitis, and sleep-disordered breathing, as these commonly coexist with asthma and eczema 1. Spirometry should be performed whenever asthma is suspected, and this evaluation should be repeated on follow-up visits, particularly in children 1.