| Primary cause | Risk factors or mechanisms | Major evaluation method (in addition to clinical findings) |
| Pulmonary causes |
| Aspiration* (recurrent small volume) | - Primary swallowing dysfunction or laryngeal disorders (eg, laryngeal cleft, tracheoesophageal fistula), gastroesophageal reflux, achalasia
| - Swallowing assessment (eg, videofluoroscopic) and other evaluation as indicated¶
|
| Asthma, cough-dominant asthma* | - Genetics, environment, atopy, postacute respiratory infections
| - Spirometry, FeNO, airway hyperresponsiveness
|
| Chronic endobronchial suppurative disease* (protracted bacterial bronchitis, chronic suppurative lung disease, bronchiectasis) | - Cystic fibrosis
- Immunodeficiency (primary or secondary)
- Primary ciliary dyskinesia
- Aspiration
- Postinfection (eg, tuberculosis, pneumonia, etc)
| - Sweat test, genetic screening
- Evaluation of immune function
- Cilia biopsy, genetic testing
- Chest CT, bronchoscopy
- Refer to "Aspiration" above
|
| Chronic pneumonia* | - Chronic atelectasis, mucous plugging, plastic bronchitis
- Pathogens include tuberculosis, nontuberculosis mycobacteria, mycoplasma, fungi, and chlamydia
| - Chest CT, bronchoscopy
- Relevant microbial assessment (eg, QuantiFERON gold and Gene Xpert for tuberculosis)
|
| Eosinophilic lung disease* | - Primary or secondary (ie, related to parasitic disease)
| - Bloods and bronchoalveolar lavage
|
| Inhaled retained foreign body* | - Young child, history of choking (even if days or weeks before cough onset)
| |
| Interstitial lung disease* | - Primary genetic abnormality, post-severe infection bronchiolitis obliterans, autoimmune disease, radiation, drugs
| - Relevant genetic or autoimmune test (with or without lung biopsy), chest CT
|
| Mechanical inefficiency | - Tracheobronchomalacia and other airway anomalies
- Vascular rings or other anomalies that cause tracheal narrowing
| - Dynamic bronchoscopy
- Chest CT with contrast
- Chest MRI (if vascular cause suspected)?
|
| Noninfective bronchitis* | - Exposure to environmental pollutants (eg, tobacco smoke, fungi, traffic)
| - History and removal of trigger
|
| Postinfection (self-resolving) | - Viral infections, pertussis, parapertussis
| |
| Space-occupying lesions* | | |
| Extrapulmonary causes |
| Causal role likely |
| Cardiac* | - May cause cough due to airway compression, pulmonary edema, or arrhythmia
| - ECG and other evaluation as indicated
|
| Ear disease* | - Oto-respiratory reflex (Arnold reflex), in which stimulation of the auricular branch of the vagus nerve triggers cough
| - Examination of the ear canal and removal of the object, or treatment of disease that is triggering the cough
|
| Tic cough (habit cough) or somatic cough disorder (psychogenic cough)* | - May be isolated, but more likely if other tics are present
- Some children have generalized anxiety or disproportionate anxiety about the seriousness of their symptoms
| - Suppressibility, distractibility, suggestibility, variability, and presence of a premonitory sensation; cough absent during sleep
- Response to behavioral therapy (eg, suggestion therapy)Δ
- Children with somatic cough disorder may require referral to a psychologist and/or psychiatrist if unresponsive to suggestion therapy
|
| Medications* | - ACE inhibitors (common), any inhaled medication, proton pump inhibitors, other drugs (uncommon)
- Certain other medications (eg, cytotoxic drugs) may be associated with interstitial lung disease
| - Discontinuation of medication
- Evaluation for interstitial lung disease (eg, HRCT)
|
| Causal role unlikely |
| Esophageal disorders | - Gastroesophageal reflux (acid and nonacid) and eosinophilic esophagitis
| - Esophageal pH monitoring or impedance monitoring, with or without endoscopy
|
| Upper airway pathology | - Chronic sinusitis, obstructive sleep disorders◊
| - Evaluation guided by suspected disorder (CT, polysomnography)
|
