How is child daytime cough not too cough to return a responsibility at night

The child coughs during the day and does not cough at night. It may be allergic cough, because there are many things in contact during the day, and it is likely to be exposed to allergens, such as dust mites, pollen, etc. Secondly, it may be pneumonia or bronchitis and other diseases. It is necessary to go to the hospital for a detailed respiratory examination.