Nasal polyps are growths on the lining of the nasal passages or sinuses.
Larger nasal polyps can block your nasal passages or sinuses and cause breathing difficulties, a loss of sense of smell, frequent sinus infections and other problems.
Nasal polyps are more common in adults, particularly those with asthma, frequent sinus infections and allergies.
Children with cystic fibrosis also often develop nasal polyps.