Colds, prolonged crying spells, and constant activity also can cause your child's nose to run. If your child has a runny nose associated with a cold, don't try to stop it. Most of the time, the mucus will be clear and watery as long as there is no infection. Gentle and frequent blowing will help keep nasal passages relatively clear. If your child has a runny nose, but no cold, then he or she may have allergic rhinitis.
Allergic rhinitis is caused by allergies to certain plants, pollen, or dust.
If your child has such an allergy, try to keep him or her away from the allergic agent and follow home treatment procedures for hay fever. May have a runny nose due to seasonal allergies and symptoms are severe. Has a runny nose, without any other symptoms, lasting three or more weeks. Experiences wheezing, shortness of breath, or difficulty swallowing. Tugs at ear or complains of an earache.