Possible diagnosis and specific investigations to be considered
| Specific pointers to diagnosis | Suggested specific diagnosis | Investigations |
| Sudden onset cough | Inhaled foreign body | Bronchoscopy |
| Barking/brassy cough | Airway malacia | Bronchoscopy |
| Paroxysmal cough with classic inspiratory ‘whoop’ | Pertussis syndrome | Serology for Bordetella, Mycoplasma, Chlamydia |
| Wheezing episodes/atopy/exertional dyspnoea/chest hyperinflation/pectus deformity | Asthma | Spirometry (±bronchodilator responsiveness) |
| Rhinitis, allergic salute, throat clearing | Allergic rhinitis | Allergy testing; trial of treatment |
| Choking with feeds/chesty post feeds/neurodevelopmental abnormality | Recurrent aspiration | CXR, barium swallow/pH/impedance studies, videofluoroscopy, bronchoscopy and BAL |
| Wet cough, poor growth, features of malabsorption, nasal polyps, purulent sputum, finger clubbing | Bronchiectasis (various causes, eg, cystic fibrosis, primary ciliary dyskinaesia) | CXR, sweat test, genotyping, sputum culture, HRCT, nasal brushings, bronchoscopy |
| Recurrent infections, wet cough | Immune deficiency | Immune function tests |
| Progressive cough, weight loss, fever, night sweats and haemoptysis | Tuberculosis | CXR, Mantoux test, gastric aspirate for acid-fast bacilli, sputum culture |
| Dry cough and breathless | Interstitial lung disease | CXR, spirometry, HRCT, lung biopsy |
| Abnormal cardiac examination, exertional dyspnoea, hypoxaemia | Cardiac disease | CXR, echocardiogram, cardiology referral |
| Honking, bizarre cough/cough disappears in sleep | Psychogenic cough | CXR, spirometry, avoid over-investigation which may reinforce problem |
| Mucopurulent drainage, chronic nasal obstruction, facial pain or pressure | Sinusitis | Imaging of the sinuses and/or an empirical trial of treatment |
| Medication history (ACE inhibitors/illicit drugs) | Drug reaction | Change/stop drug Measure level |
BAL, bronchoalveolar lavage; CXR, chest X-ray; HRCT, high-resolution CT.