A runny nose (rhinorrhea) is a symptom with mucus from the nose, usually caused by a viral infection or allergy. It is often accompanied by nasal congestion, sneezing, itching.
It occurs with colds, flu, allergic rhinitis. Nasal rinsing and symptomatic remedies can provide relief, depending on the cause. A runny nose is often a manifestation of rhinitis (inflammation of the nasal mucosa).