Running nose

A running nose, or runny nose, also known as rhinorrhea (American English) and also spelled as rhinorrhoea or rhinorrhœa (British English), is the free discharge of a thin mucus fluid from the nose; it is an extremely common condition. It is a common symptom of allergies (hay fever) or certain viral infections, such as the common cold or COVID-19. Rhinorrhea varies in color and consistency depending upon the underlying cause. It can be a side effect of crying, exposure to cold temperatures, cocaine abuse, or drug withdrawal, such as from methadone or other opioids. Treatment for rhinorrhea may be aimed at reducing symptoms or treating underlying causes. Rhinorrhea usually resolves without intervention, but may require treatment by a doctor if symptoms last more than 10 days or if symptoms are the result of foreign bodies in the nose.

The term rhinorrhea was coined in 1866 from the Greekrhino- ("of the nose") and -rhoia ("discharge" or "flow").