Sinusitis, also referred to as rhinosinusitis, is an inflammation of the sinus membranes that can be caused by a variety of reasons. Depending on the underlying cause, sinusitis can present a variety of symptoms, such as sinus congestion, sinus discharge, sinus pressure, and facial pain or headaches.

Sinusitis can be either infectious or non-infectious. A virus or bacteria causes infectious sinusitis, while allergies are often the cause of non-infectious sinusitis. The medical community divides sinusitis into two basic categories: acute or chronic.

Acute Sinusitis

Acute bacterial sinusitis, the more prevalent form, is usually caused by a viral cold. Computer tomography (CT) scans reveal that more than 80% of viral colds cause sinus inflammation. Typically, this inflammation — like the cold itself —resolves within two weeks.

However, about 2% of colds in adults and about 20% in children are complicated by a secondary bacterial infection. Most healthy people harbor certain bacteria in their upper respiratory tracts. These bacteria are kept in check until the body's defenses are weakened or a cold blocks drainage from the sinuses. When this happens, nasal swelling and narrow sinus outflow passages can trap the normally harmless bacteria. The trapped bacteria suddenly begin to multiply, causing acute bacterial sinusitis.

Chronic Sinusitis

Chronic sinusitis is defined as sinusitis that persists for at least 12 weeks. Chronic sinusitis sometimes develops because of sinus blockage. The condition affects an estimated 32 million Americans and has become a multi-million-dollar industry for pharmaceutical companies that market symptom-relieving sinus medications.

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