Objective: In children, post-nasal drip (PND)-induced cough is speculated. However, the relationship between PND and cough is still unclear.
Methods: During acute exacerbation of asthma, the number of overnight coughs and the cough pattern were compared in the children with atopic asthma with PND (n = 8) and the children with atopic asthma without PND (n = 27). All subjects had allergic rhinitis according to our original cough monitor.
Results: The total number of overnight coughs was significantly higher in the subjects with PND than in the subjects without PND (P < 0.05). In contrast, the overnight cough pattern of the subjects with PDN was found to be the same as in the subjects without PND, showing an increase in the number of coughs at the sleep onset and in the early morning.
Conclusion: Our results suggest that PND may increase the number of nighttime coughs in children with atopic asthma and allergic rhinitis. In contrast, the overnight cough pattern was the same in the two groups, suggesting that this specific cough pattern is due to allergic inflammation of the upper and lower airways.