Unfortunately, there is no consensus amongst experts as to what precisely causes nose polyps. Opinions vary from..

• Severe allergies
• Diet
• Bacterial or viral infections
• A response to an environmental factor or fungi
• Genetic weaknesses
• Cystic fibrosis (in rare cases only)

Moreover, the exact chain of events that triggers the formation of sinus polyps has not been established.  However, the best consensus is that of chronic inflammation and how the immune system in your mucus membranes appears to contribute to that inflammation. This response results in an accumulation of fluid in the nasal and sinus cavities, with the force of gravity causing a reaction resulting in the formation of polyps in nose.

The polyps usually develop near the openings of the sinuses, but can be found anywhere throughout the nasal passages or sinuses.

It is important to point out that although they share the same name, there is no connection between nasal polyps and polyps that form in the colon.