Nasal polyps can impair breathing, and a protein strand (VEGF) may be the cause.

Nasal Polyps are teardrop-shaped growths that form in the nasal and sinus mucosa lining. They may be single or resemble a grape like structure. Small nasal polyps may cause no problems but as they grow larger in size they can block your nasal passages or sinus cavities and cause breathing difficulties, loss of smell and a swollen face.

Nasal polyps form slowly from swelling of the sinus mucosa lining. In the past we believed that this swelling was caused by chronic sinus conditions such as environmental allergies, sinusitis, hayfever and asthma. But now a study has shown that Nasal Polyps may be caused by a protein called vascular endothelial growth factor (VEGF), which stimulates the blood vessel to grow and bypass blocked vessels. This causes an overgrowth of cells, causing nasal polyps to develop.

So while allergies, sinusitis and asthma may put a person at risk of developing nasal polyps, it may not be the actual cause of it.