A few coughs in an 8-month-old child may be caused by the following factors: 1. Environmental factors, as the child’s throat is sensitive, if he inhales excessively dry air or breathes in unpleasant gases, it will stimulate his throat and lead to a few coughs. 2. The coughing symptoms can be aggravated if the child is not actively treated, and can even lead to coughing up sputum.