Clinical Definition

Sinusitis is an infection or inflammation of the mucus membranes of the sinuses. Swelling of the membranes can obstruct normal drainage, which can lead to the growth of bacteria and development of an infection. Sinusitis may be allergic, bacterial, viral, and/or may involve structural abnormalities. Clinical presentation of acute sinusitis usually includes headache, fever and localized pain and pressure under the eyes.

In Our Own Words

The sinuses are hollow structures located in the bony framework behind the nose and around the eyes. Sinuses have a lining or membrane that helps to filter, moisten and warm the air you breathe. Sinusitis, or the inflammation or infection of one or more of these sinuses, may be acute or chronic. Allergies and infections, typically viral, can cause the membranes in the sinuses to swell. The inflammation causes typical sinusitis symptoms, such as headache and facial pressure. The swelling blocks the normal flow of mucus, which may lead to a secondary bacterial sinusitis.