Nasal polyps are common, noncancerous, teardrop-shaped growths that form in the nose or sinuses, usually around the area where thesinuses open into the nasal cavity. Mature nasal polyps look like seedless, peeled grapes.
Often associated with allergies or asthma, nasal polyps may cause no symptoms, especially if they’re small, and require no treatment. But larger nasal polyps can block normal drainage from the sinuses. When too much mucus accumulates in the sinuses, it can become infected, which accounts for the thick, discolored drainage in the nose and throat that affects many people with nasal polyps.
Nasal polyps shouldn’t be confused with the polyps that form in thecolon or bladder. Unlike these types of polyps, they’re rarely malignant. Usually, they’re thought to result from chronic inflammation or a family tendency to develop nasal polyps.Nor should nasal polyps be confused with swollen turbinates, which are the normal tissue that lines the side of the nose. Unlike swollen turbinates, they’re not painful to the touch.
Nasal polyps grow in inflamed tissue of the nasal mucosa. The mucosa is a very wet layer that helps protect the inside of your nose and sinuses and humidifies the air you breathe. During an infection or allergy-induced irritation, the nasal mucosa becomes swollen and red, and it may produce fluid that drips out. With prolonged irritation, the mucosa may form a polyp. A polyp is a round growth (like a small cyst) that can block nasal passages.