The reason why one year old babies cough without running nose is usually lower respiratory tract infections, allergies and so on. 1. Lower respiratory tract infections: because the baby’s respiratory system is not fully developed, so when violated by viruses or bacteria, it is easy to produce bronchitis, bronchitis and other lower respiratory tract infections, so that the baby coughs but not runny nose symptoms. 2. Allergy: because the baby’s respiratory system is not fully developed is also more sensitive, so for pollen, cold air and other stimuli are more sensitive, will make the baby allergic reaction, cough without running nose symptoms. One year old baby not runny nose cough, there may be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.