Cough in children may arise from causes anywhere along the airway, from the nose to the alveoli. Cough is a nonspecific reaction to irritation anywhere from the pharynx to the lungs. Childhood coughing is a common problem that can cause anxiety in parents. There are important differences from adult cough in terms of likely causes and management guidelines.
In the British Thoracic Society (BTS) guidelines, chronic cough in children is defined as a cough lasting longer than eight weeks. This timeframe is used because most simple infective causes of cough will resolve in 3-4 weeks, and the eight-week definition identifies those who may need further investigations. These guidelines note that the timeframe between acute and chronic cough (3-8 weeks) is sometimes called 'subacute cough' or 'prolonged acute cough' (eg, a slowly resolving post-viral cough). If a cough is starting to resolve after three weeks, further time may be allowed before investigating further. However, if the cough is not improving by the third week or is increasing in severity, earlier investigations may be indicated.
In other guidelines, including those from the American College of Chest Physicians, and the Thoracic Society of Australia and New Zealand, chronic cough is defined as a cough lasting more than four weeks.[2, 3, 4]
These guidelines are based on the natural history of the most common cause of acute cough, upper respiratory tract infections. Studies suggest that in 90% of children with acute upper respiratory tract infections, the cough has settled within 25 days.
There is a wide range of possible causes. The three most common causes of chronic cough in adults (asthma, postnasal drip syndrome and gastro-oesophageal reflux) are not necessarily the most common in children.Isolated cough is now thought to be unusual as a presentation of asthma in children, which usually is associated with other presenting symptoms.
Common causes in primary care
- Infections (or recurrent infections) - including respiratory syncytial virus (RSV), adenovirus, Mycoplasma pneumoniae, chlamydial pneumonia, whooping cough (pertussis) and tuberculosis.
- Postnasal drip syndrome.
- Environmental agents - tobacco smoke, possibly charcoal or kerosene heaters.
- Gastro-oesophageal reflux.
Less common causes
- Inhaled foreign body.
- Cystic fibrosis.
- Immune deficiency.
- Congenital lesions - eg, tracheo-oesophageal fistula, tracheomalacia.
- Ciliary dyskinesia.
- Neurological - eg, tics, psychogenic cough. Psychogenic cough may be bizarre, honking and decrease with sleep or attention to other activities.
- For a full list of other causes, see the BTS guidelines.
Make an initial assessment, looking for pointers towards a specific cause, and for any 'red flags' (see box).
- Nature of cough:
- The sound - eg, brassy or seal-like (suggests tracheal/glottic irritation); bizarre or honking (suggests psychogenic).
- Wet or dry (productive or not) - NB: young children don't expectorate sputum but may vomit it.
- Haemoptysis or sputum.
- Onset, duration, time course of cough.
- Does the cough disappear when sleeping?
- Other symptoms - including fever, weight loss, night sweats.
- Family history - especially atopy or respiratory disease.
- Medication. Cough is a common side-effect of angiotensin-converting enzyme (ACE) inhibitors.
- Cigarette smoke exposure or other environmental pollutants - eg, heating fuel.
- General features - fever, height/weight and any failure to thrive, clubbing, lymphadenopathy, signs of atopy.
- Upper airway - abnormal voice or crying, inspiratory stridor, ENT examination.
- Respiratory signs - dyspnoea, respiratory rate, chest auscultation.
- Observation of the cough if possible.
Pointers to particular causes of chronic cough
- Neonatal onset of cough - consider congenital malformations, aspiration, lung infections, cystic fibrosis.
- Very acute onset - inhaled foreign body.
- Child well, no other symptoms - consider nonspecific isolated cough, recurrent viral bronchitis, psychogenic cough, habit cough (dry repetitive cough which disappears with sleep).
- Systemic ill health or recurrent pneumonia - consider tuberculosis, inhaled foreign body, cystic fibrosis, immune disorders, persistent bronchitis, recurrent aspiration.
Nature of cough
- Associated with wheezing or breathlessness - consider asthma, inhaled foreign body, recurrent pulmonary aspiration, cardiac disease, airways compression, tracheobronchomalacia, bronchiolitis.
- Associated shortness of breath and restrictive lung defect - interstitial lung disease.
- Cough occurs in paroxysmal spasms with an inspiratory 'whoop' - whooping cough.
- Cough is brassy, croupy or bizarre and honking - consider tracheal or glottic irritation and psychogenic causes.
- 'Wet' or productive cough (most young children do not expectorate sputum but tend to swallow it) - consider bronchiectasis or any suppurative lung condition - eg, cystic fibrosis.
- Relentlessly progressive cough - consider inhaled foreign body, lobar collapse, tuberculosis, rapidly expanding intrathoracic lesion.
- True haemoptysis (apparent haemoptysis may be related to nosebleeds, cheek biting or haematemesis) - consider pneumonia, lung abscess, bronchiectasis, retained inhaled foreign body, tuberculosis, pulmonary hypertension.
- Exercise/excitement/cold air/nocturnal cough/change in environment (eg, pets) - consider asthma.
- Swallowing/meals - recurrent aspiration.
- Lying down - postnasal drip, gastro-oesophageal reflux.
- Attention - psychogenic.
- Mannerisms associated with unusual stereotypical coughs - suggest Tourette's syndrome (although the diagnosis of Tourette's syndrome cannot be made on a single tic, including isolated cough).
- Family history of lung disease.
- Neonatal onset.
- Sudden onset.
- Haemoptysis (true haemoptysis - not, for example, nosebleeds or cheek biting).
- Cough with feeding, dysphagia, severe vomiting.
- Chronic moist cough with sputum production.
- Night sweats/weight loss.
- Continuous unremitting or worsening cough.
- Signs of chronic lung disease - eg, clubbing.
- Failure to thrive.
- Abnormal voice or crying, inspiratory stridor.
- Focal chest abnormality.
Which children need investigating in primary care?
Belgian primary care guidelines suggest the following strategy:
- 'Red flags' present - require specific investigations depending on the clinical picture.
- No 'red flags':
- If fever - exclude pneumonia.
- For immigrants - exclude tuberculosis.
- If there are pointers to a specific cause - investigate appropriately (eg, spirometry, serology, oesophageal pH monitoring).
- If there are no specific pointers - consider CXR.
BTS guidelines suggest the following strategy when investigating chronic cough:
- Spirometry where possible in older children ± tests of bronchodilator responsiveness or bronchial hyper-reactivity.
- Obtain a sputum sample if possible - for microbiology and cytology.
- Allergy testing (skin prick or radioallergosorbent test (RAST) specific testing) may help if atopy/asthma are likely diagnoses.
- Other tests will depend on the clinical picture and differential diagnosis.
Trial of treatment:
- BTS guidelines suggest that in contrast with adults, for children with a dry cough who are well and have no specific disease pointers, empirical trials of treatment (for asthma, allergic rhinitis or gastro-oesophageal reflux) are unlikely to be beneficial and are generally not recommended.
- However, in young children, BTS suggests that, as it may be difficult to rule out asthma as a cause of coughing in young children, a trial of anti-asthma therapy may be used (eg, inhaled corticosteroids). Ensure effective delivery, adequate doses and clear recording of outcomes.
- Set a time (eg, 8-12 weeks) after which the trial of anti-asthma medication should be stopped. If the child has responded to anti-asthma therapy and the treatment has subsequently been stopped, an early relapse that again responds to treatment is suggestive of cough-variant asthma. If there is no response, asthma is unlikely.
- This depends on any specific cause found.
- In a well child with no 'red flags', aim to avoid invasive investigations and to explore the expectations and anxieties of parents. Persistent cough causes a significant burden in terms of repeated consultations and parental anxiety.
- Remove environmental contributions if possible - eg, tobacco smoke.
- No treatment has been found to be particularly effective for isolated nonspecific cough in an otherwise well child. Reassurance is important, and it will usually subside over time.
- Antitussive drugs, other than simple cough linctus, are not generally recommended.
Further reading and references
; Evaluation of the patient with chronic cough. Am Fam Physician. 2011 Oct 1584(8):887-92.
; Levels of pollutants in indoor air and respiratory health in preschool children: a systematic review. Pediatr Pulmonol. 2009 Mar44(3):231-43. doi: 10.1002/ppul.20965.
; British Thoracic Society Cough Guideline Group (2008)
; Guidelines for evaluating chronic cough in pediatrics: ACCP evidence-based clinical practice guidelines. Chest. 2006 Jan129(1 Suppl):260S-283S.
; Cough in children: definitions and clinical evaluation. Med J Aust. 2006 Apr 17184(8):398-403.
; CICADA: Cough in Children and Adults: Diagnosis and Assessment. Australian Cough Guidelines summary statement. Comment. Med J Aust. 2010 Jun 7192(11):671.
; Duration of symptoms of respiratory tract infections in children: systematic review. BMJ. 2013 Dec 11347:f7027. doi: 10.1136/bmj.f7027.
; Chronic productive cough in school children: prevalence and associations with asthma and environmental tobacco smoke exposure. Cough. 2006 Dec 272:11.
; Prolonged cough in children: a summary of the Belgian primary care clinical Prim Care Respir J. 2008 Dec17(4):206-11.
; What is the burden of chronic cough for families? Chest. 2008 Aug134(2):303-9. doi: 10.1378/chest.07-2236. Epub 2008 Jul 18.
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