| Pattern | Cause | Potential investigations | ||||
| Frequently recurring viral bronchitis | Episodic, frequent in winter, associated with “head colds”, may occur “back-to-back” | Viral infections | None | |||
| Crowded living conditions, ETS and attendance in child care nursery | Chest radiography | |||||
| Examine during a period when symptom-free | ||||||
| Postviral cough | Troublesome cough (day and night) following a respiratory infection and slowly resolving over next 2–3 months | Viral respiratory infections, Chlamydia and Mycoplasma infections | None, chest radiography, serology | |||
| Consider trial of asthma therapy (some mild asthmatics have prolonged recovery from each viral infection) | ||||||
| Pertussis and pertussis-like illness | Troublesome spasmodic cough after initial respiratory infection which slowly resolves over 3–6 months. Vomiting clear tenacious mucus. Older child may complain of difficulty catching breath | Bordetella pertussis, parapertussis, adenovirus, influenza, parainfluenza | Nil | |||
| Chest radiograph, positive serology or culture may be helpful in reducing requirements for further investigation | ||||||
| Cough variant asthma | Isolated cough (no wheezing) due to asthma. Confidence in diagnosis increased when strong atopic background present and cough responds rapidly to anti-asthma medication but relapses when stopped | Asthma | None, chest radiograph. Is airways obstruction present and reversible? | |||
| BHR or BDR tests, | ||||||
| Is there eosinophillic inflammation? Induced sputum, allergy tests, FeNO, response to asthma medication | ||||||
| Allergic rhinitis, postnasal drip and sinusitis – cough likely due to concomitant tracheobronchial inflammation | Not fully accepted as a cause of cough. Cough when “head hits the pillow” or constant throat clearing by day. May have transverse nasal crease of “allergic salute” | Causes of allergic rhinitis | ENT examination, often no investigations needed | |||
| Chest radiography, allergy tests | ||||||
| Response to antirhinitis treatment within 2 weeks | ||||||
| CT scan of sinuses | ||||||
| Psychogenic cough | Usually an older child/adolescent(1) Tic-like “habit cough” persisting after head cold or during times of stress(2) Bizarre disruptive honking cough with child exhibiting “la belle indifference”. Cough goes away with concentration or sleep | Underlying stress | It is important to do investigations to assure the doctor and parent that no major disease is being missed. However, it is important not to keep performing futile investigations that may reinforce the underlying problem | |||
| Bizarre honking cough usually serving a purpose with some secondary gain | ||||||
ETS, exposure to environmental tobacco smoke; FeNO, fractional exhaled nitric oxide concentration; BDR, bronchodilator responsiveness; BHR, bronchial hyperreactivity.