Sinusitis can be caused by allergies. Using too much decongestant nasal sprays, smoking, swimming or diving can also increase the risk of sinusitis. 

Some patients have growths called nasal polyps that block their sinus passages and cause sinusitis.

When sinusitis is caused by a bacterial or viral infection, the patient suffers from a sinus infection. Sinus infection may occur after one has a cold. The cold virus attacks the lining of the sinuses which cause them to swell and become narrow. The body will respond to the virus by producing more mucus which gets blocked up in the swollen sinuses. This built-up of mucus creates an environment for bacteria to grow. The bacteria can cause a sinus infection.

Sinuses are the air chambers in the bone behind the cheeks, eyebrows and jaw. They produce mucus, a fluid that cleans bacteria and other particles out of the air one breathes. Tiny hairs called cilia will sweep mucus out of one’s sinuses so it can be drained out through the nose.

Saline nasal spray will clean the nasal passages and help clear congestion. 

Decongestant may be prescribed to help drain the sinuses which may cause sinus pain or pressure. They are generally only recommended for short-term use. 

Over-the-counter pain relievers such as acetaminophen and ibuprofen can help ease headache and sinus pain. 

In the case of very severe sinusitis, and if it is caused by bacteria, an antibiotic may be prescribed for 10 to 14 days. It is important to complete the course of the antibiotics.