Chronic cough is a common presenting symptom in children, although most will have no serious underlying cause.
If the severity or frequency of the cough causes alarm, there are a number of differential diagnoses to consider.
The accuracy and reliability of symptom reporting are key factors in the assessment of cough.
Parental reporting of cough does not correlate well with the frequency, duration or intensity of the actual cough measured objectively.
It would appear in many cases that the reported 'severity' of coughing in a child is related to how it affects the parents or teachers.
Parental discrimination between a wet and a dry cough has good predictive value for the presence of secretions in the lower airway, in contrast to the poor reliability of reporting of wheeze and stridor.
In a child with isolated cough, a history and examination, followed by targeted investigations if necessary, should allow the child to be placed in one of five diagnostic categories.
These are: the well child; the child with a serious illness such as cystic fibrosis or TB; the child with non-serious but treatable causes of cough and wheeze (e.g. gastroesophageal reflux or postnasal drip); the child with an asthma syndrome; or an overestimation of symptoms for psychological or other reasons by the child or family.
Clinical evaluation of cough in all children should include an assessment of environmental factors, in particular tobacco smoke, parental concerns and parental expectations.
Causes of cough
In some children the quality of cough is recognisable and suggestive of specific aetiology. Barking or brassy cough is suggestive of tracheomalacia; a paroxysomal cough with/without whoop is suggestive of pertussis and parapertussis infection; a chronic wet cough, especially in mornings, is suggestive of suppurative lung disease, such as bronchiectasis.
In older children, cough may be associated with psychological problems because, as in adults, cough can be cortically modulated. So-called psychogenic cough should always be considered a differential in the older child. Typically, the cough disappears completely during sleep.
Isolated chronic cough is a poor marker of asthma. Without other typical features, asthma should not be considered on the basis of cough alone. Cough-predominant or cough-variant asthma undoubtedly exists, but is a rare diagnosis.
Bronchial hyper-responsiveness or reversible airways obstruction are both key features of asthma, which can help to identify children with cough-predominant asthma.
The type and depth of the investigations depends on clinical findings and the suspected aetiology. Hence, possible relevant investigations range from simple tests, such as oxygen saturations, to invasive tests, including chest high-resolution CT scan, bronchoscopy, barium swallow and sleep study.
The key decision to be made is whether there are sufficient features to justify referral to secondary care.
Treatment should always be preceded by a systematic effort to exclude serious underlying illness and establish a specific diagnosis. Over-the-counter cough medicines are not useful, and cough suppressants may be actively dangerous.
Management of the otherwise well child with a persistent, dry non-productive cough will include reassurance and monitoring.
Empirical trials of asthma, allergic rhinitis or gastroesophageal reflux treatments are unlikely to be beneficial and are not recommended.
In the management of any child with cough, irrespective of the aetiology, attention to exacerbating factors is encouraged. The cessation of parental smoking has been found to be a successful form of therapy.
Behavioural counselling for smoking mothers has been shown to reduce young children's exposure to environmental tobacco smoke in both reported and objective measures of environmental tobacco smoke.
Cough in children is very common and, in the majority, is reflective of expected childhood respiratory infections in an otherwise healthy child.
However, cough may also be the first sign of a significant serious disorder. All children with chronic cough should have a thorough clinical review to identify any features suggestive of an underlying respiratory and/or systemic illness that merits referral for investigation.
- Dr Gupta is specialist registrar and Professor Bush is honorary consultant paediatric chest physician, Royal Brompton Hospital, London.
1. Shields M, Bush A, Everard M, McKenzie S, Primhak R. BTS guidelines: Recommendations for the assessment and management of cough in children. Thorax 2008; 63 (Suppl 3): iii1-iii15.
2. Gupta A, McKean M, Chang A. Management of chronic non-specific cough in childhood: an evidence-based review. Arch Dis Child Educ Pract Ed 2007; 92(2): 33-9.
Potentially serious lung disorders with coughing
- Cystic fibrosis
- Immune deficiencies
- Primary ciliary disorders
- Protracted bacterial bronchitis
- Recurrent pulmonary aspiration
- Retained inhaled foreign body
- Anatomical disorder (bronchomalacia or lung malformation)
- Interstitial lung disease
|History and examination of the child|