what causes a runny nose

A runny nose can be caused by various factors, including infections such as colds, flu, or sinusitis, as well as allergies. Rhinitis, which involves irritation and swelling inside the nose, is a common cause of a runny nose. Other potential causes include rhinorrhea, which is mucus dripping from the nose, and conditions like cold and dry air, allergies, and the common cold. The consistency and color of the mucus can vary, with watery nasal discharge typically caused by allergies, spicy food, or cold temperatures, while thicker mucus is usually produced during a cold or other infection. Its important to note that a runny nose will usually clear up on its own, but certain treatments can help improve the symptoms. If a runny nose persists for more than three weeks without a known allergy, its advisable to seek medical attention.