Sinusitis simply means your sinuses are infected or inflamed, but this gives little indication of the misery and pain this condition can cause. Health care experts usually divide sinusitis cases into

• Acute, which last for 3 weeks or less
• Chronic, which usually last for 3 to 8 weeks but can continue for months or even years
• Recurrent, which are several acute attacks within a year

Sinusitis is a leading cause of morbidity and poor quality of life issues.

WHAT ARE SINUSES?

Sinuses are hollow air spaces in the face. When people say, "I'm having a sinus attack," they usually are referring to symptoms in one or more of four pairs of cavities, or sinuses, known as paranasal sinuses . These cavities, located within the skull or bones of the head surrounding the nose, include the

• Frontal sinuses over the eyes in the brow area
• Maxillary sinuses inside each cheekbone
• Ethmoid sinuses just behind the bridge of the nose and between the eyes
• Sphenoid sinuses behind the ethmoids in the upper region of the nose and behind the eyes

Each sinus has an opening into the nose for the free exchange of air and mucus, and each is joined with the nasal passages by a continuous mucous membrane lining. Therefore, anything that causes a swelling in the nose—an infection, an allergic reaction, or another type of immune reaction—also can affect the sinuses. Air trapped within a blocked sinus, along with pus or other secretions, may cause pressure on the sinus wall. The result is the sometimes intense pain of a sinus attack. Similarly, when air is prevented from entering a paranasal sinus by a swollen membrane at the opening, a vacuum can be created that also causes pain. This kind of pain is often experienced in an air journey during the descent.