Diagnosis

Your doctor can usually make a diagnosis based on your answers to questions about your symptoms, a general physical exam and an examination of your nose. Polyps may be visible with the aid of a simple lighted instrument.

Other diagnostic tests include:

• Nasal endoscopy. A narrow tube with a lighted magnifying lens or tiny camera (nasal endoscope) enables your doctor to perform a detailed examination inside your nose and sinuses.

• Imaging studies. Images obtained with computerized tomography (CT) can help your doctor pinpoint the size and location of polyps in deeper areas of your sinuses and evaluate the extent of swelling and irritation (inflammation).

  These studies may also help your doctor rule out other possible blockages in your nasal cavity, such as structural abnormalities or another type of cancerous or noncancerous growth.

• Allergy tests. Your doctor may suggest skin tests to determine if allergies are contributing to chronic inflammation. With a skin prick test, tiny drops of allergy-causing agents (allergens) are pricked into the skin of your forearm or upper back. Your doctor or nurse then observes your skin for signs of allergic reactions.

  If a skin test can't be performed, your doctor may order a blood test that screens for specific antibodies to various allergens.

• Test for cystic fibrosis. If you have a child diagnosed with nasal polyps, your doctor may suggest testing for cystic fibrosis, an inherited condition affecting the glands that produce mucus, tears, sweat, saliva and digestive juices.

  The standard diagnostic test for cystic fibrosis is a noninvasive sweat test, which determines whether your child's perspiration is saltier than most people's sweat is.

• Blood test. Your doctor may test your blood for low levels of vitamin D, which are associated with nasal polyps.