[Definition and nosological aspects of chronic cough in children].

Cough is a physiological reflex occurring when sensitive receptors located in upper airways and the larynx are activated. By definition a 'chronic cough' lasts at least 3 weeks. An analysis of clinical characteristics is essential for setting up the diagnosis and giving correct treatment. We can individualize three mainly clinical aspects: the young child of less than 3 years of age, the nocturnal cough and the productive cough. The 'variant of asthma' cough is a common problem among all ages that frequently goes unrecognized. Any patient with dry nocturnal coughing that lasts more than three weeks should have an empiric bronchodilator treatment. The prognosis is on the whole favourable.