Table 1. A logical approach to the diagnosis of chronic cough for children.

The simplest and least-invasive diagnostic tool is history, which can make the diagnosis of habit cough (A) and provides historical pointers to consider diagnoses that require specific testing or therapeutic trial (B–F).

A. Observation and history: frequency of cough—repetitive cough absent once asleep indicates likelihood of habit cough syndrome B. Cough present for <3 months, especially if spasmodic and disturbs sleep, requires consideration of pertussis syndrome C. Cough in infant with feeding warrants textured swallow study D. Cough present since neonatal period, history of transient tachypnea of newborn, and chronic otitis media warrants consideration of primary ciliary dyskinesia E. Cessation of cough after a short course of an oral corticosteroid is consistent with asthma; further evaluation can determine an appropriate treatment plan. Failure to stop cough with the oral corticosteroid warrants further evaluation F. A 2-week therapeutic trial of amoxicillin-clavulanate can be considered as an alternative to bronchoscopy and lavage if the historical pointer suggests a “wet” cough in an infant or toddler in making a clinical diagnosis of protracted bacterial bronchitis       1. Radiology, chest X-ray or computerized axial tomography             a. Lobar hyperinflation suggests retained foreign body—consider rigid bronchoscopy             b. Suggestion of airway inflammation or bronchiectasis warrants sweat chloride testing for cystic fibrosis             c. Situs inversus totalis suggests a likelihood of primary ciliary dyskinesia             d. Normal chest X-ray warrants further evaluation       2. Flexible fiberoptic bronchoscopy with bronchoalveolar lavage can determine the following:             a. Airway malacia, trachea or bronchi             b. Protracted bacterial bronchitis