Nasal polyps are growths inside the nose or sinuses that don't cause pain. Experts don't know what causes nasal polyps. Infections, allergies or any condition that causes long-term irritation and swelling, also called inflammation, in the nose or sinuses can increase the risk of having nasal polyps.

Nasal polyps are linked to irritation and swelling of the inside of the nose and sinuses that lasts more than 12 weeks. Small nasal polyps might not cause symptoms. Larger nasal polyps can block the nose. Symptoms may include a runny, stuffy nose; mucus running down the throat; not being able to smell or taste; and facial pain.

Treatment depends on the cause of the swelling and irritation. The condition can be treated with steroids, biologic medicines, other medicines or surgery.