Sinusitis (Sinus Infection) Causes
In most people, the cause of an acute sinus infection (sinusitis) is a virus. However, this is not always the case. Other causes include bacteria or even fungi. The specific cause of chronic sinusitis is unknown, but certain people have a higher chance of developing it, such as those with allergies, a weakened immune system, or an aspirin sensitivity.
What Causes Sinus Infections (Sinusitis)?Sinusitis is a medical term used to describe inflammation (swelling and irritation) of the sinuses. There are several different types -- the two most common are acute and chronic sinusitis. This article will look at what can cause each of these sinusitis types.
Acute Sinusitis CausesAcute sinusitis is diagnosed in people who have had symptoms for fewer than four weeks. Most often, this condition is caused by a virus (acute viral sinusitis) or bacteria (acute bacterial sinusitis).
Acute Viral Sinusitis Causes
About 98 percent of acute sinusitis cases are caused by a virus. The most common viruses are similar to those that cause the common cold, and include:
This is why it is common for people to get a sinus infection with a cold.
Causes of Acute Bacterial Sinusitis
When the sinuses become inflamed, there is an increased risk for a bacterial sinus infection. Research has shown that bacteria cause acute sinusitis in up to 2 percent of all cases in adults and up to 13 percent in children.
The most common bacteria responsible for these infections include:
- Streptococcus pneumoniae
- Haemophilus influenzae
- Moraxella catarrhalis.
The first two are by far the most common causes, accounting for more than three out of every four cases of bacterial sinusitis.
(Click Sinusitis Risk Factors for things that increase the risk for a bacterial sinus infection.)