If your child has a runny nose, you may be suffering from a cold or allergic rhinitis. 1. Upper respiratory tract infections: When you have a cold, your child may have the symptom of a runny nose, as well as other symptoms such as cough, fever, loss of appetite and fatigue. 2. Allergic rhinitis: in addition to the common cold, allergic rhinitis can also cause the child to run a clear nose, but generally no fever, fatigue, loss of appetite and other symptoms, but there can be a clear family history of allergies, but also can be combined with asthma and other diseases, you can improve the blood routine, nasopharyngoscopy to assist in the diagnosis. Found that children keep running a clear nose, generally speaking, colds are relatively common, if suspected of allergic rhinitis, should go to the hospital for standardized diagnosis and treatment, so as not to delay the condition.