How do nasal polyps affect the sinuses?

Polyps are grape-like swellings that come from the lining of the sinuses. As they grow they can block the tiny channels of the sinuses and cause build-up of mucus which can lead to acute and chronic sinusitis. Further polyp growth can block the airway and make nose breathing difficult. It is not uncommon for severe nasal polyps to decrease or block the sense of smell entirely. Asthma can be worsened by polyps and they can cause sleep apnea which is obstruction of the airway while sleeping. 

Nasal polyps are usually your body's reaction to an adverse event that manifests themselves as bulges in the lining of the nasal tissue. Polyps pose several problems but most often are associated with reduced airflow through the nose when you take a nasal breath or they may swell and block the sinuses from draining properly. While they can often be treated with sprays and/or medications, in some situations, surgical intervention is necessary to remove the polyps.