Cough could be the first obvious sign of disease especially of the airways or lungs and when it is representing more than a defense mechanism. Also, by its persistence it can become a helpful indicator of any potential disease for both patient and the physician.

Alternatively, impairment or absence of the cough mechanism might be harmful and even fatal. This is one of the reasons why cough suppression is not indicated in childhood. Paediatricians are more concerned about the etiology of the cough for arriving at the right diagnosis. Chronic cough in adults is universally defined as a cough that lasts for more than 8 weeks, whereas in childhood, different timings are reported. Several explanations support the definition of a cough lasting for more than 4 weeks in preschool children as chronic cough, but this is true when the cough is wet.

In childhood, the respiratory tract and nervous system experience a series of anatomical and physiological processes of maturation influencing the cough reflex. Furthermore, immunological response undertakes developmental and memorial processes making infection and congenital abnormalities the devastating causes of cough in preschool children.

Cough in children must be treated on the basis of etiology, and there is no evidence supporting the use of medication for symptomatic cough relief or implementing empirical methods. In preschool age, many cases of chronic cough are caused by protracted bacterial bronchitis, foreign body aspiration, trachea-bronchomalacia, post-infectious cough or some other combination of these. The other causes of chronic cough are asthma, bronchiectasis, gastroesophageal reflux, and upper respiratory syndrome that are less frequent in this age group. The incidence of each cause depends on the population in consideration, the infectious diseases epidemiology, socioeconomic factors, and the local healthcare system.

Source: Kantar A, Bernardini R, Paravati F, Minasi D, Sacco O. Chronic cough in preschool children. Early Hum Dev. 2013 Oct;89 Suppl 3:S19-24. doi: 10.1016/j.earlhumdev.2013.07.018. Epub 2013 Sep 2. PMID: 24008117.