What is the best approach to manage a 4-week persistent cough in a child with asthma who uses albuterol (bronchodilator) for wheezing?

Management of Persistent Cough in a Child with Known Asthma

In a child with known asthma experiencing a persistent cough for 4 weeks, a systematic evaluation for potential causes beyond asthma is strongly recommended rather than simply increasing asthma medications. 1

Initial Assessment

Evaluate Cough Characteristics

• Determine if cough is wet/productive or dry
• Assess timing (day vs. night, with exercise)
• Note associated symptoms (wheezing, shortness of breath)

Look for Red Flag Symptoms

• Digital clubbing
• Failure to thrive
• Hemoptysis
• Feeding difficulties
• Recurrent pneumonia
• Hypoxia 2

Diagnostic Approach

1. Chest radiograph - Recommended for all children with chronic cough (>4 weeks) 2

2. Spirometry with bronchodilator response - For children >6 years old 2

3. Consider specific causes:

   • Protracted bacterial bronchitis (PBB) - Common cause of wet cough
   • Post-infectious cough - Can persist 3-8 weeks after respiratory infections
   • Foreign body aspiration - Should always be considered, even in children with asthma 3
   • Upper airway disorders - Including rhinosinusitis
   • Pertussis or mycoplasma infection 1, 2

Management Algorithm

If Cough is Wet/Productive:

1. Prescribe 2 weeks of antibiotics targeting common respiratory bacteria (Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis) 1

   • First choice: Amoxicillin for children under 5 years
   • Alternatives: Co-amoxiclav, cefaclor, or macrolides 2

2. If cough resolves within 2 weeks of antibiotics, diagnose as protracted bacterial bronchitis (PBB) 1

3. If cough persists after initial 2-week course:

   • Extend antibiotic treatment for an additional 2 weeks 1, 2
   • If still persistent after 4 weeks of appropriate antibiotics, consider further investigations (flexible bronchoscopy, chest CT) 1

If Cough is Dry:

1. Assess current asthma control:

   • Review technique and adherence with albuterol
   • Evaluate if controller medication is needed

2. Consider a time-limited trial of asthma therapy:

   • If risk factors for asthma are present, consider a 2-4 week trial of inhaled corticosteroids (400 μg/day of beclomethasone equivalent) 1
   • Important: Cough unresponsive to ICS should not be treated with increased doses 1

3. If no response to asthma therapy:

   • Discontinue asthma medications that aren't helping
   • Consider alternative diagnoses 4

Important Cautions

1. Avoid overdiagnosis of asthma - Studies show that persistent cough alone is often misdiagnosed as asthma, leading to medication overuse 4

2. Limit empirical treatment - Do not use empirical approaches aimed at treating upper airway cough syndrome, GERD, or asthma unless other features consistent with these conditions are present 1

3. Set time limits for therapeutic trials - Any empirical trial should be of defined limited duration to confirm or refute the hypothesized diagnosis 1

4. Address environmental factors - Determine exacerbating factors such as environmental tobacco smoke exposure 1

5. Schedule follow-up - Reassess within 2 weeks to evaluate response to treatment 2

When to Refer

• If cough persists despite appropriate management
• If specific cough pointers suggesting underlying disease are present
• If cough persists after 4 weeks of appropriate antibiotics 1, 2

Remember that cough in children with asthma without a co-existent respiratory infection is usually dry, and the sensitivity and specificity of cough as a marker for wheeze is poor (34% and 35%, respectively) 1. Many children with persistent cough are incorrectly diagnosed with asthma, leading to unnecessary medication use with potential side effects 4.