Mucus, Cold, Flu, Rhinorrhea, Cold, Allergies, Sinusitis, Nasal congestion, Stuffy nose, Runny nose, Nasal discharge, Rhinitis. Root Cause of Disease A runny nose can be caused by anything that irritates or inflames the nasal tissues. Infections such as the common cold and allergies and various irritants may all cause a runny nose. Less commonly, a…
