Nasal polyps are growths in the lining of the nose, usually attached by a small stalk. Their cause is unknown, although they are more common in people with asthma or rhinitis (inflammation of the lining of the nose).
Small polyps may not cause symptoms, but if they are large or numerous, symptoms may include a stuffy or runny nose, reduced sense of smell, snoring, and postnasal drip (mucus dripping from the back of the nose down the throat).
They may also sometimes lead to recurrent sinusitis (inflammation of the sinuses).
Treatment is usually with medication (including nasal spray); large polyps may need to be removed by surgery.