Risk factors

Any condition that triggers long-term irritation and swelling (inflammation) in your nasal passages or sinuses, such as infections or allergies, may increase your risk of developing nasal polyps.

Conditions often associated with nasal polyps include:

• Asthma, a disease that causes the airway to swell (inflame) and narrow
• Aspirin sensitivity
• Allergic fungal sinusitis, an allergy to airborne fungi
• Cystic fibrosis, a genetic disorder that results in abnormally thick, sticky fluids in the body, including thick mucus from nasal and sinus linings
• Churg-Strauss syndrome (eosinophilic granulomatosis with polyangiitis), a rare disease that causes the inflammation of blood vessels
• Vitamin D deficiency, which occurs when your body doesn't have enough vitamin D

Your family history also may play a role. There's some evidence that certain genetic variations associated with immune system function make you more likely to develop nasal polyps.