Rhinorrhea, commonly known as a runny nose, consists of an unusually significant amount of nasal discharge. It is a symptom of the common cold and of allergies (hay fever). The term comes from the Greek words â€œrhinosâ€ meaning â€œof the noseâ€ and â€œrhoiaâ€ meaning â€œa flowing.â€
Rhinorrhea is a frequently encountered condition that is usually not dangerous. The discharge may be colored or thick as a result of conditions such as sinusitis. It may be accompanied by Post-nasal drip that may also aggravate coughing or result in a sore throat. Other secondary consequences include Ear infections or sinusitis, especially if increased mucus levels block the Eustachian tube or the sinus passages.
Rhinorrhea may be due to allergic conditions such as hay fever or foreign materials within the nostril. Bacterial or viral infections such as the common cold, influenza or sinusitis may also be accompanied by a runny nose. Nasal discharges may also be present in cases of vasomotor rhinitis, a non-infectious and non-allergenic condition.
Head injuries may also cause excess nasal discharges. Basilar skull fracture may result in cerebrospinal fluid rhinorrhea.
Environmental causes include contact with strong smelling substances such as disulfide compounds found in Onions and garlic, both of the genus Allium. CS gas, which provides an especially intense pepper-like odour, also results in this symptom. This phenomenon is caused by the same mechanism that causes a runny nose when crying: tears drain through the inner corner of the eyelids through the nasolacrimal duct, and finally into the nasal cavity, where they manifest as a runny nose.
Thinner nasal discharges reduce the risk of sinus and ear infections. Non-medicinal means to achieve this include drinking additional fluids and increasing indoor humidity with a humidifier.
Medicinal treatment includes antihistamines (e.g., diphenhydramine or loratadine) to reduce the amount of nasal discharge and saline nasal sprays. Vasoconstrictor nasal sprays may also be applied for a limited time, but their use may become counterproductive after several days, causing Rhinitis medicamentosa.