Cough

Rewritten against the 2024 CICADA (Cough in Children and Adults: Diagnosis, Assessment and Management) statement, which separates adult and paediatric diagnostic algorithms (the adult ones resting on a thinner trial-evidence base) and newly prioritises culturally-specific management of chronic wet cough in First Nations children.

Key facts

Cough is the commonest manifestation of a lower respiratory tract infection, can have a psychogenic basis, and may persist for many weeks after an infection resolves. Upper airway cough syndrome (previously “post-nasal drip”) is the commonest cause of persistent chronic cough — classically worse at night as secretions track down the larynx.

Commonest causes of haemoptysis: URTI (24%), acute/chronic bronchitis (17%), bronchiectasis (13%), TB (10%), cancer (4%), unknown (22%).

Normal CXR	Abnormal CXR
Chronic bronchitis/asthma	COPD/bronchiectasis
GORD (symptomatic/asymptomatic)	Interstitial lung disease
Drug-induced (ACEi, inhaled steroids)	Cystic fibrosis
OSA	Inhaled foreign body (esp. children)
Chronic sinusitis	TB
Functional	Heart failure

Clinical approach

Associated symptoms provide the most diagnostic information — breathlessness, wheeze, constitutional symptoms.

History: smoking; occupational exposures (asbestos; mining — silicosis/ pneumoconiosis; bird handling — psittacosis/allergic alveolitis); recurrent childhood infections (CF, bronchiectasis); hayfever/eczema → asthma; family history of emphysema (alpha-1 antitrypsin deficiency); TB exposure.

Timing:

• Nocturnal: asthma, LVF, upper airway cough syndrome, chronic bronchitis, whooping cough
• On waking: bronchiectasis, asthma, bronchitis, GORD
• After meals: hiatus hernia, oesophageal diverticulum, tracheo-oesophageal fistula
• With wheeze: asthma
• With breathlessness: asthma, COPD, LV failure

Examination: Horner’s syndrome (constricted pupil, ptosis) — consider an apical lung tumour; fine crackles (pulmonary oedema from CCF, ILD, early lobar pneumonia); coarse crackles (resolving pneumonia, bronchiectasis, TB).

Haemoptysis

Always requires investigation. Commonest cause is an acute chest infection.

Cough in children

A common source of parental anxiety. Most children with chronic cough do not have asthma. CXR is advisable if persistent.

Acute cough

Duration thresholds: in children, acute = up to 2 weeks, prolonged acute = 2–4 weeks, chronic = >4 weeks. In adults, acute = up to 2 weeks, chronic = >8 weeks. Acute cough is, almost by definition, benign, and the Australian cough guidelines (CICADA) focus on chronic rather than acute cough.

Causes:

• Acute bronchitis — the most common cause of acute cough in general practice, usually with LRTI symptoms, may be productive or non-productive
• Asthma — usually with associated chest tightness/wheeze
• Drug-induced cough (ACEi, beta-blockers) — the temporal relationship to starting the drug isn’t always close; stopping the agent and seeing resolution within 1–4 weeks strengthens the diagnosis
• Inhaled foreign body — usually sudden onset, may start while a child is eating; consider with localised wheeze on auscultation
• Pneumonia (focal signs, fever), URTI, influenza, croup (barking cough, may be sudden-onset without a viral prodrome as in spasmodic croup)

Chronic cough (CICADA framework)

Probability-based diagnosis (if examination, CXR and spirometry are normal):

• Adults: asthma, rhinosinusitis, GORD
• Children: protracted bacterial bronchitis, asthma (if other symptoms also present)
• Exposures to consider: post-infective cough, tobacco smoke/ environmental pollutants

Alarm symptoms (adults): haemoptysis, >20 pack-year smoker, smoker >45 with a new/changed cough, prominent dyspnoea, substantial sputum production, hoarseness, fevers/weight loss, GORD with alarm features (weight loss, anaemia, haematemesis/melaena, odynophagia, dysphagia, non-response to usual treatment), feeding difficulties, abnormal CXR.

Alarm symptoms (children): prominent breathlessness, recurrent wet-sounding productive cough (think CF), systemic symptoms (fever, weight loss, failure to thrive), recurrent pneumonia, stridor, abnormal respiratory examination, abnormal CXR.

Significant conditions not to miss (adults): cancer of the larynx, bronchus or lung; parenchymal lung disease (COPD, ILD, bronchiectasis, sarcoidosis); infection (TB, lung abscess, pertussis); cardiovascular (LVF, pulmonary infarction, aortic aneurysm).

Significant conditions not to miss (children): congenital airway abnormalities, foreign body inhalation, parenchymal lung disease (cystic fibrosis, sarcoidosis/fibrosis/bronchiectasis), infection (TB, lung abscess, pertussis).

Conditions with a remediable cause:

• Protracted bacterial bronchitis — especially children <5; a wet cough >4 weeks in an otherwise well child. Ideally diagnosed in consultation with a paediatrician, as a prolonged antibiotic course is needed and other causes should be excluded first. Treat with high-dose amoxicillin- clavulanate for 2–4 weeks.
• Asthma, GORD, OSA, ACEi-induced cough, eosinophilic bronchitis
• Children: motor tic, habitual cough, psychogenic cough

Chronic cough differential (eTG summary)

Cause	Notes
Postviral cough	Follows an acute viral URTI/acute bronchitis; may last up to 8 weeks
Protracted bacterial bronchitis	Wet cough >4 weeks in children, particularly <5 years
Pertussis	Consider if persistent and paroxysmal, lasting 2–6+ weeks
GORD	Consider with heartburn/water brash, or cough worse at night/after eating; often a clinical diagnosis or response to empirical treatment
Upper airway cough syndrome (previously “post-nasal drip”)	May reflect excessive mucus production or increased perception of normal mucus volumes
Upper airway dysfunction (vocal cord dysfunction)	Can be triggered by any cough cause and worsened by GORD, smoke/fume exposure, or vocal overuse
Obstructive sleep apnoea	Pharyngeal inflammation from snoring may contribute
Psychogenic/habit cough	Particularly children; not present overnight
Retained inhaled foreign body	Sudden onset, especially if it began while eating or playing with small objects
Tuberculosis	With or without sputum/fever/weight loss; consider with a relevant travel/birth-country history or impaired immunity
Lung or laryngeal cancer	Consider in smokers >45 with a new/altered cough or voice disturbance
Recurrent aspiration	Consider with Parkinson’s disease, stroke, dementia, COPD, impaired consciousness, or bulbar neuromuscular disease
Chronic bronchitis	Productive cough, daily, >3 months for ≥2 years; occurs in most heavy smokers (>20 pack-years)
Bronchiectasis	Productive cough with frequent chest infections
Interstitial lung disease	Dry cough, often with dyspnoea
Cystic fibrosis	Productive cough with GI symptoms or failure to thrive
Drug-induced cough	ACE inhibitors and beta-blockers are common precipitants; onset isn’t always closely temporally related to starting the drug