Sinusitis is almost always due to an infection, although the swelling caused by allergies can simulate the symptoms of pressure, pain and congestion. and allergies can set the stage for a bacterial infection. Bacteria are the most common cause of sinus infection. Streptococcus pneumoniae causes about 33% of all cases, while Haemophilus influenzae causes about 25% of all cases. Sinusitis in children can be caused by Moraxella catarrhalis (20%). In people with weakened immune systems (including patients with diabetes, acquired immunodeficiency syndrome or AIDS and patients taking medications that lower their immune resistance, such as cancer and transplanted patients), sinusitis can be caused by fungi such as Aspergillus, Candida, or Mucorales
Chronic sinusitis occurs when the problem has existed for at least three months. There is rarely a fever with chronic sinusitis. Sinus pain and pressure are frequent, as is nasal congestion. Due to the nature of breast swelling, they may not be able to drain the nose. The drain, therefore, constantly drips down the back of the throat, which results in a continuous sore throat and bad breath.
The diagnosis is sometimes complicated, because the symptoms often resemble those of a cold without complications. However, sinusitis should be strongly suspected when a cold persists for more than a week.
Doctors have different levels of confidence in certain basic tests commonly performed in the office. For example, touching on the breasts may a procedure called “sinus transillumination” may or may not be useful. Using a flashlight pressed against the skin of the cheek, the doctor will observe in the patient’s open mouth. When the breasts are full of air (in normal conditions), the light will be projected through the breast, and will be visible on the roof of the mouth as an illuminated and reddened area. When the breasts are full of mucus, the light will stop. While this simple test may be useful, it is certainly not a perfect way to diagnose or rule out the diagnosis of sinusitis.
X-rays and CT scans of the paranasal sinuses are useful for acute and chronic sinusitis. People with chronic sinusitis should also be checked for allergies; and they may need a procedure with a scope to see if some type of anatomical obstruction is causing their disease. For example, the septum (the cartilage that separates the two nasal cavities from each other) may be slightly displaced, called a deviated septum. This can cause a chronic obstruction and cause the person to develop an infection.