How to identify and manage prolonged acute and chronic cough in pre-school children

Coughing is one of the most common complaints causing children to visit their local healthcare provider​[1,2]​. Problem coughing, both acute and chronic, in young children is very distressing and disruptive, especially when it is interfering with sleep and activity. It can similarly be very disruptive for parents and cause anxiety​[3–5]​. This article highlights the common causes of cough in children, describes its assessment and outlines a management approach for pre-school children who present in the community with either prolonged acute or chronic coughing.

Pathophysiology

Cough can be defined as a forced, expulsive manoeuvre against a closed glottis, which is associated with a characteristic sound (see ‘Case-based learning: cough’). The cough reflex is vital to prevent the inhalation of foreign material and assist the expulsion of mucus and phlegm when there is excessive production​[6]​.

Cough classification

The British Thoracic Society’s (BTS’s) guidelines on cough in children provide definitions for acute, recurrent, prolonged acute and chronic cough​[6]​:

• Acute cough — cough of recent onset, lasting <3 weeks is defined as acute. It is usually self-limiting and is commonly caused by upper respiratory tract infections (URTIs), including simple head colds, acute bronchitis and croup.  
• Prolonged acute cough — often starts acutely and lasts longer than 3 weeks but less than 8 weeks​[6]​. It is also usually self-limiting and likely caused by airway cough receptor hyper-responsiveness, following infections such as Mycoplasma pneumoniae or Bordetella pertussis (whooping cough, where a post-infectious cough can persist for a median of 112 days)​[7–10]​.
• Recurrent acute cough — repeated cough episodes (>2 per year) are experienced, with each lasting for more than 7–14 days. It can be difficult to differentiate between a pre-school child with normal, recurrent, acute cough and one with chronic cough, as they may have frequent back-to-back URTIs with short well intervals, with some children experiencing 4–11 URTIs during the winter months​[6,10]​.

When a ‘watch and wait’ approach is appropriate for children with a prolonged acute cough

Around 10% of otherwise healthy children coughing with a head cold are still coughing after 3–4 weeks; therefore a ‘watch and wait’ approach until cough resolution may be appropriate​[6,11]​. In children without signs and symptoms of a serious underlying disease process and suffering from a dry, isolated cough (e.g. no associated wheezing) the recommended approach is to watch, wait and review​[6,12]​ (6,12). Box 1 outlines important practice points that should be considered​[13]​.

However, there are three situations when a ‘watch and wait’ approach is not appropriate for a child with a prolonged acute cough​[6]​. These can be considered as red flags and include:

1. A relentlessly progressive cough — this may simply be a symptom of post-viral/infectious cough or pertussis-like illness that has not yet reached its peak. However, if the cough is progressing and becoming more frequent, more uncomfortable or more productive, the following causes must be considered:
   • a retained, inhaled foreign body;
   • an airway compression (e.g. by an expanding extra intrathoracic mass or tuberculosis node), with or without lobar collapse.
2. If the cough is ‘wet’, productive and phlegmy — this is a sign of excessive secretions in the large airways and likely indicates persistent bacterial bronchitis (PBB); an early antibiotic may prevent the cough becoming chronic​[14]​. It is important to note that pre-school children are usually unable to produce a sputum sample but rather swallow their airway secretions. Therefore, it may not be possible to document a ‘wet’ cough without the help of a physiotherapist. In infants, a wet cough may be associated with a ‘rattly’ chest resulting from upper tracheal and bronchial secretions.
3. If there are signs of chronic disease, the cough may be its first presentation — notable features to look for include:
   • poor growth parameters;
   • finger clubbing;
   • coughing up blood;
   • chest signs (e.g. thin but overinflated chest wall, crackles and wheezes on auscultation, raised respiratory rate and increased working breathing, including indrawing of the rib cage).

The Figure below shows a simplified algorithm to the approach to a child with prolonged acute coughing.

Chronic cough

The presence of a persistent cough for more than 8 weeks is defined as chronic cough​[6]​. Causes include post-infectious coughs, protracted bacterial bronchitis (PBB), asthma and asthma-like conditions​[10]​. Children presenting with a chronic cough and no known underlying diagnosis should have a detailed history taken using specific questions for chronic cough (outlined below). Clinical examination is important alongside history taking and should include growth assessment, chest shape, work of breathing and auscultation for chest signs​[12,15]​.

Assessment of chronic cough

When diagnosing chronic cough, it is important to obtain relevant information to develop a detailed history that includes when and how the cough started, its trajectory, characteristics and triggers, as well as whether coughing is isolated or occurs with other features​[6,12,14]​. The following questions provide a structure for history taking that healthcare professionals can use.

1. When did the cough start?

This question allows an estimation of the cough duration and potential red flags​[6,15]​. If coughing started in the neonatal period or early infancy and persists, this is suggestive of:

• Congenital airway anomaly (e.g. laryngeal cleft or small undiagnosed tracheo-oesophageal fistula), often associated with recurrent milk aspiration during feeding;
• Recurrent milk aspiration owing to incoordinate suck-swallow reflexes;
• An in-utero lung infection (e.g. chylamdia pneumonia, causing a staccato-like cough);
• Primary ciliary dyskinesia, a genetic condition whereby the cilia of the airway epithelial cells fail to move bronchial secretions up so that they can be subsequently swallowed​[16–19]​.

Children with a history of coughing from early infancy should be referred to a paediatric specialist for further investigations.

2.  How did the cough start?

If the child had signs of a head cold (i.e. a runny nose, sneezing, and a sore throat) but is otherwise well and the cough trajectory suggests it is resolving, then a ‘watch and wait’ approach can be justified (see Box 1). Prolonged coughing after a head cold suggests a post-viral or post-infectious cough​[10,20]​.

If the child did not have a head cold, it should be confirmed whether the cough started abruptly, with or without a witnessed choking episode. Young children often put objects into their mouths and are therefore at risk of inhaling them. It is important to remember that the choking episode may not have been witnessed and the choking long since stopped. A child with a sudden onset cough, especially if progressive, should be referred urgently to a paediatric unit with ENT specialists for a bronchoscopy to exclude or remove a foreign body​[21]​.

3.  What is the trajectory of the cough? 

If the cough is resolving and the child appears well and physical examination is otherwise normal then a ‘watch and wait’ approach is appropriate​[11]​. However, it is important to review the child at around four to six weeks to ensure the cough has resolved and before it becomes chronic (lasting more than eight weeks).

If the cough is relentlessly progressing then pertussis-like illness, TB, a retained inhaled foreign body, or an external compression on airway should be considered​[6]​. Urgent referral to a paediatrician should be made for further investigations.

4.  What are the characteristics of the cough?

Is the cough wet, moist and phlegmy with a ‘rattly’ chest, or is it a dry cough?

A persistent wet cough suggests excessive airway secretions and can be indicative of persistent or PBB​[22–25]​. Children with postnasal drip (e.g. associated with allergic rhinitis) will have either a dry irritating cough or a wet cough where they need to clear their throat often​[26,27]​.

A persistent dry cough is often associated with post-infectious coughs, cough-variant asthma, non-specific isolated cough (often nocturnal), and psychogenic or somatic coughs, which are typically seen in older children.

Other types of cough

The cough with pertussis or pertussis-like infections is spasmodic and occurs in paroxysms triggered by movement, laughing, feeding or a change in air temperature. The paroxysmal spasmodic cough may be accompanied by an inspiratory whooping sound.

A barking, brassy or seal-like cough features in anomalies of the trachea, glottis or upper bronchi (e.g. tracheobronchomalacia)​[28]​.

5.  Is the cough an isolated symptom?

Wheezing is a symptom of the reversible airway obstruction that occurs in asthma​[29]​. Children with asthma cough more than normal and an increase in coughing can occur at the start of a developing asthma attack. Auscultation of the chest is important because the presence of wheezing means an asthma diagnosis is likely. Associated allergies (e.g. allergic rhinitis, atopic eczema, food allergies, strong family history of asthma) help support an asthma diagnosis and suitable treatment should commence as per guidelines​[29]​. Most children with a non-specific, isolated, dry cough do not have asthma but a small number do (cough-variant asthma). If cough-variant asthma is suggested, then a trial of asthma treatment should be started (see ‘Persistent dry cough that could be asthma’).

6. What triggers the cough?

Coughing triggered by exercise, laughing or cold air may be linked to asthma​[29]​. Coughing that starts after the child lies down may suggest postnasal drip or gastro-oesophageal reflux.

Coughing with feeding in infants suggests the possibility of recurrent pulmonary aspiration​[16,17]​.

Management of chronic cough

The principle underlying management of chronic cough in children is to find and treat the underlying cause, rather than trying to suppress the symptom​[6]​. It is always sensible to try and reduce the child’s exposure to environmental pollutants, especially those within the household (e.g. tobacco smoke).

There is little evidence supporting the safe use of antitussive medications to suppress cough in pre-school children with prolonged acute and chronic cough. Cough suppressant medication has recently and comprehensively been reviewed​[27,30,31]​. Most medications have little evidence of effectiveness or safety for reducing acute coughing. In general, antitussives, antihistamines, decongestants and expectorants are not recommended for pre-school children​[6,30]​. The NHS website suggests considering giving children aged over one year with a distressing cough a warm drink of lemon and honey; although not a treatment for chronic cough, it may help provide transient relief during periods when the coughing is particularly distressing​[31]​.

Reassurance may be all that is required for children with a dry chronic cough and no disease specific symptoms. It is important to explain to parents that cough is a normal protective reflex and that the natural history of coughing with URTI is resolution, but that around 1 in 10 children will develop prolonged cough that should eventually resolve​[32,33]​. Parents may put pressure on healthcare professionals to ‘do something,’ but there is little evidence to support pharmacological or non-pharmacological intervention. Empathy is needed when supporting parents or carers of children who have heightened cough reflex or develop a prolonged cough each time they suffer from a head cold. Healthcare professionals should therefore know when reassurance and a ‘watch and wait’ approach should be used.

In primary care, two common situations can occur that require further discussion: the child with a persistent dry cough that could be asthma and the child with a persistent wet cough that could be PBB.

Persistent dry cough that could be asthma

The likely cause of a persistent dry cough is cough-receptor hypersensitivity being slow to resolve after an upper airway infection, although natural resolution eventually occurs. Chang et al. showed that a ‘watch and wait’ approach was safe for children with a chronic dry cough and no specific clinical pointers​[11]​. Bronchial lavage studies have shown that few children have allergic eosinophils in their airways, as occurs in asthma​[34,35]​. This makes it difficult to exclude asthma as a cause, especially when no wheezing has been heard. A trial of asthma treatment is, therefore, often used to confirm an asthma diagnosis (see Box 2)​[36–38]​.

Persistent wet cough which could be protracted bacterial bronchitis

Chronic bronchitis with an accompanying wet cough has not been recognised as a single disease entity in paediatric medicine, with conditions such as cystic fibrosis (CF), immune deficiencies, reduced mucus clearance (primary ciliary dyskinesia), recurrent pulmonary aspiration and a retained, inhaled foreign body requiring exclusion​[39]​.  

Persistent bacterial infection of the airway wall in each of these conditions can eventually result in fixed dilated bronchi and the child can end up with bronchiectasis.

More recently Chang and Everard reported that many otherwise well pre-school children had a persistent wet productive cough and named this PBB rather than chronic bronchitis​[22,23]​. In PBB, bronchial lavage fluid showed an increase in neutrophils and bacteria and Chang et al. reported that PBB may be a precursor of bronchiectasis​[14,22,25]​.

Although the gold standard for diagnosis of PBB requires bronchoscopy and secretion culture, this is invasive for young children; guidelines from the European Respiratory Society (ERS) recommend an empiric two-week course of antibiotics (co-amoxiclav)​[25]​. A good response to the antibiotic supports PBB diagnosis, but PBB tends to relapse, and several courses of antibiotic may be required. Indeed, a randomised controlled trial involving 106 children (median age 2.2 years) comparing a 4-week with a 2-week course of co-amoxiclav reported little advantage in immediate cure but showed a significantly longer time to next wet cough (median 150 days for 4-week course versus median 36 days for 2-week course). The rate of recurrence was also reduced (53% vs. 74%)​[40]​.

Prompt diagnosis and treatment of PBB leads to improved quality of life for both the child and family and reduces future disease risk​[23,25]​. PBB is common and many children have no underlying condition other than mild tracheobronchomalacia, which often resolves as the child grows​[28]​. Many are effectively cured after a single or second course of antibiotic and the ERS PBB guidelines recommend that those children that fail to respond to a second antibiotic course should be referred to a specialist paediatrician for further investigations to rule out conditions, such as CF, immune deficiencies and primary ciliary dyskinesia​[19]​. However, there are major concerns with empiric antibiotic treatment in primary care, including the potential for overdiagnosis and hence overuse of antibiotics in children from low-risk populations. In addition, healthy pre-school children who experience recurrent viral bronchitis can have an initial dry cough followed by a wet cough. This cycle of frequent recurrent acute coughs with only short cough-free intervals can lead to a child seeming to have a chronic wet cough. Giving recurrent courses of antibiotics without obtaining culture specimens is not good antimicrobial stewardship.

Summary

Important principles on how to identify and manage prolonged acute and chronic cough in pre-school children for pharmacists to remember are outlined below:

• Prolonged acute and chronic cough are common in pre-school children and can cause family anxiety and reduced quality of life;
• Common causes of prolonged acute and chronic cough in the pre-school child include post-infectious cough, PBB and asthma/asthma-like conditions;
• A ‘watch and wait’ approach with reassurance is appropriate if a child has post-infectious cough, is otherwise well and the cough trajectory is towards resolution. Resolution should be confirmed;
• Children with a persistent wet cough and likely PBB should be treated with a 2–4 week course of co-amoxiclav or other suitable antibiotic. Failure of resolution or recurrence should trigger a referral for further investigations;
• Where asthma is a suspected diagnosis (e.g. possible cough-variant asthma), a trial of asthma therapy is indicated. This trial should be time limited and a decision made as to whether the cough was responsive. A second response to asthma therapy makes asthma likely;
• When using a trial of asthma therapy to confirm an asthma diagnosis, it is important to ensure the therapy has been delivered correctly and at the proper frequency. Using a validated cough questionnaire score is useful as an objective outcome.
• It can be difficult to differentiate the otherwise well child who is experiencing frequent recurrent acute infections, each with coughing, from the child with true chronic cough;
• History is important for the identification of red flags for underlying conditions that need early diagnosis, such as a retained foreign body, PBB, CF, immune deficiency and primary ciliary dyskinesia;
• Since coughing is a vital protective reflex, the use of cough suppressants is not advised and the underlying principle of management is to first identify the underlying cause and address this.