Persistent cough in children: when to reassure, investigate and refer

In the first of a new series on Dilemmas in Paediatrics, GPSI in paediatrics Dr David Capehorn discusses management of the common but tricky presentation of persistent cough in children, including identifying red flags, avoiding overdiagnosis of asthma and how to recognise protracted bacterial bronchitis  

Persistent cough is one of the most common reasons for paediatric consultations in primary care and a frequent source of parental anxiety.

In most children, a cough reflects recurrent viral upper respiratory tract infections and resolves spontaneously. However, persistent cough may occasionally represent significant underlying pathology, including asthma, protracted bacterial bronchitis (PBB), bronchiectasis, aspiration syndromes, foreign body inhalation or, less commonly, tuberculosis and congenital airway abnormalities.

The central challenge for GPs is therefore not simply treating the cough itself, but distinguishing the well child with recurrent self-limiting illness from the child with important ‘red flag’ features requiring further investigation or referral.

Definition and prevalence

Chronic cough in children is defined as a cough lasting more than four weeks.¹ This threshold reflects the well-established evidence that the vast majority of post-viral coughs in children resolve well within this period: in 90% of children, acute cough following a viral upper respiratory tract infection resolves within 25 days.² Chronic cough affects approximately 5–10% of children at any one time and represents a substantial proportion of paediatric consultations in primary care.

The character of the cough is often highly informative. One of the most clinically useful distinctions in paediatric cough assessment is whether the cough is wet or dry. A persistent daily wet cough is always pathological until proven otherwise and should prompt consideration of airway infection or suppurative lung disease.

Diagnosis and management – key principles

Young children rarely expectorate sputum effectively, so the terms ‘productive’ and ‘non-productive’ are often less useful in paediatrics than simply asking whether the cough sounds wet or dry. If uncertainty exists, asking parents to record the cough on a mobile phone can be extremely helpful.

A dry cough is more commonly associated with post-viral cough, asthma, upper airway cough syndrome (previously known as post-nasal drip syndrome), or somatic (habit) cough. By contrast, a persistent wet cough suggests excessive airway secretions and should raise concern for conditions such as protracted bacterial bronchitis, bronchiectasis, aspiration syndromes, cystic fibrosis or primary ciliary dyskinesia.

The temporal pattern also matters considerably. Children with recurrent viral infections are usually well between episodes and often have symptom-free intervals. Conversely, a cough occurring daily for weeks without remission deserves further assessment.

Practical management approaches according to cough type

1. The well child with recurrent viral or post-viral cough

Young children commonly experience multiple viral upper respiratory tract infections each year, particularly after starting nursery or school. It is entirely normal for some children to experience six to eight viral illnesses annually. Typically, the cough gradually improves over two to three weeks and the child remains otherwise well, with preserved exercise tolerance, normal growth, and normal examination findings. These children often have symptom-free intervals between infections.

Management in primary care centres primarily on reassurance, explanation of the natural history of viral illness, and clear safety-netting advice. Repeated antibiotics are rarely beneficial in uncomplicated post-viral cough.

2. Chronic dry cough

A chronic dry cough without red flag features may reflect post-viral airway hyperreactivity, upper airway cough syndrome, asthma, or somatic (habit) cough. Asthma remains an important diagnosis to consider, but significant caution is required when diagnosing asthma based on isolated cough alone. A child with isolated cough is far more likely to have post-viral or habit cough than asthma.

The 2024 joint BTS/NICE/SIGN guideline³ reinforces that a diagnosis of asthma should not be confirmed without a suggestive clinical history and a supporting objective test; suspected asthma should be coded as such until formally confirmed. Most children with asthma also demonstrate wheeze, exercise limitation, nocturnal symptoms, or interval respiratory symptoms. Where asthma is suspected in a child over five years, objective tests including spirometry and bronchodilator reversibility should be sought. In pre-school children, the 2024 guideline recommends an 8–12-week trial of low-dose inhaled corticosteroid (ICS), followed by a planned withdrawal; a positive trial requires both symptomatic improvement on ICS and symptomatic worsening after withdrawal. Children who remain symptomatic without an objective response should be referred to a paediatric respiratory specialist rather than having treatment escalated empirically.

Habit (somatic) cough is worth recognising: it classically disappears entirely during sleep and may present as a repetitive barking or throat-clearing cough throughout waking hours. Most cases improve with explanation, reassurance and behavioural approaches, although some children may benefit from supportive emotional or psychological input where wider anxiety, stressors or functional symptoms are contributing.

3. Chronic wet cough

A chronic wet cough is particularly important because it usually indicates excessive lower airway secretions. One increasingly recognised condition is protracted bacterial bronchitis (PBB), now considered one of the commonest causes of chronic wet cough in pre-school children.

The European Respiratory Society (ERS) defines PBB clinically as: (i) a chronic wet or productive cough lasting more than four weeks; (ii) absence of symptoms or signs suggesting another diagnosis; and (iii) cough resolution following a 2–4-week course of an appropriate oral antibiotic.⁴

Typically, parents describe a persistent daily wet cough, often following a viral respiratory infection. Children are usually otherwise well, with normal growth and no features suggestive of asthma, bronchiectasis, cystic fibrosis or other chronic respiratory disease.

Common organisms include Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis. Co-amoxiclav is the antibiotic of choice; an initial two-week course is standard, extending to four weeks if the cough has not fully resolved. Persistence of a wet cough after four weeks of appropriate antibiotic therapy, whether partially improved or unchanged, substantially increases the probability of underlying bronchiectasis and should prompt specialist referral.⁵

Recurrent episodes of PBB (more than three per year) are a particular concern and should always prompt consideration of underlying structural airway abnormalities, including bronchiectasis, airway malacia or primary ciliary dyskinesia.

History and examination

A focused history is often highly revealing. Important questions include: whether there was a sudden onset or choking episode; whether the cough is wet or dry; whether there are nocturnal or exertional symptoms; whether the child is thriving normally; and whether there is TB exposure risk or a history of recurrent pneumonias. Environmental factors including tobacco smoke exposure and damp housing should also be explored.

Physical examination should assess growth parameters, respiratory effort, clubbing, chest wall deformity, wheeze, focal chest signs, and ENT findings suggestive of rhinitis or upper airway cough syndrome, such as nasal obstruction, mucosal inflammation, turbinate hypertrophy or visible postnasal secretions. Growth failure, clubbing, persistent crackles, hypoxia, or focal abnormalities substantially increase concern for underlying pathology.

Initial investigations in primary care

Children with red flag features or persistent symptoms despite initial management usually warrant investigation. Initial investigations may include:

• Chest X-ray.
• Spirometry (usually feasible over five years of age).
• Full blood count and inflammatory markers.
• Assessment for tuberculosis, including Mantoux or IGRA testing according to local pathways, where clinically indicated.

Normal chest radiography and spirometry do not entirely exclude significant pathology if symptoms persist or red flags remain present. In children with suspected asthma over five years old, FeNO measurement and peak flow variability may also be helpful as objective tests.³ Repeated empirical treatment escalation without reassessment should be avoided.

Key points

• Most children presenting to primary care with persistent cough ultimately have self-limiting viral illness or post-viral cough.
• However, certain features – particularly a persistent wet cough lasting more than four weeks, poor growth, clubbing, haemoptysis, recurrent pneumonia, unilateral wheeze or exertional limitation – should immediately prompt consideration of more significant pathology.
• For GPs, the key strategy is systematic assessment: determine whether the cough is wet or dry; identify red flags; assess the child’s overall wellbeing and growth; avoid over-diagnosing asthma on the basis of cough alone, particularly without objective confirmation; ensure PBB is treated with an adequate antibiotic course and followed up; and maintain a low threshold for referral where concerning features persist or fail to resolve.

References

1. Shields M et al; BTS Cough Guideline Group. BTS guidelines: Recommendations for the assessment and management of cough in children. Thorax 2008;63(Suppl 3):iii1–iii15
2. Thompson M et al. Duration of symptoms of respiratory tract infections in children: systematic review. BMJ 2013;347:f7027
3. NICE. British Thoracic Society / NICE / Scottish Intercollegiate Guidelines Network. Asthma: diagnosis, monitoring and chronic asthma management. [NG245] November 2024
4. Kantar A et al. ERS statement on protracted bacterial bronchitis in children. Eur Respir J 2017;50(2):1602139
5. Chang A et al. Use of management pathways or algorithms in children with chronic cough: CHEST guideline and expert panel report. Chest 2017;151(4):875-83
6. Gallucci M et al. When the cough does not improve: a review on protracted bacterial bronchitis in children. Front Pediatr 2020;8:433
7. Goyal V et al. Does failed chronic wet cough response to antibiotics predict bronchiectasis? Arch Dis Child 2014;99(6):522-5
8. Cheng Z et al. Approach to chronic cough in children. Singapore Med J 2021;62(10):513-9
9. Weinberger M. Chronic cough and causes in children. J Clin Med 2023;12(12):3947