Causes of Acute Sinusitis
In about 98 percent of cases, acute sinusitis is caused by a virus, such as rhinovirus or parainfluenza virus. Interestingly, the viruses that are responsible for acute sinus infections are the same viruses that cause the common cold. Other possible causes include infection with bacteria (such as streptococcus pneumoniae) or a fungus.
What Causes Acute Sinusitis?Sinusitis is a medical term used to describe inflammation (swelling and irritation) of the sinuses. When short-lived (fewer than four weeks), it is known as acute sinusitis.
Most often, acute sinusitis is caused by a virus (known as acute viral sinusitis) or bacteria (acute bacterial sinusitis). This is why the terms "sinusitis" and "sinus infection" are used interchangeably.
Causes of Acute Viral SinusitisAbout 98 percent of acute sinusitis cases are caused by a virus. When viruses enter the sinuses, they can:
- Cause swelling and inflammation
- Create thickened secretions
- Decrease the effectiveness of the sinuses' internal cleaning system.
This can result in the sinuses becoming blocked, which can eventually lead to sinus infection symptoms.
The most common viruses that cause acute sinusitis are those that also cause the common cold. They include:
This is why it is quite common for people to get an acute viral sinus infection at the same time that they have a cold.
Causes of Bacterial SinusitisResearch has shown that bacteria cause acute sinus infections in up to 2 percent of all cases in adults and up to 13 percent in children. The bacteria that most often cause acute bacterial sinusitis 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.