Sinusitis is a medical term used to describe inflammation (swelling and irritation) of the paranasal sinuses. Because many cases of sinusitis are caused by an infection, you may hear "sinusitis" and "
sinus infection" used interchangeably.
What Are the Paranasal Sinuses?
The paranasal sinuses are hollow air spaces located within the skull. They include the frontal, maxillary, ethmoid, and sphenoid sinuses. These sinuses connect to the nasal passages through an opening that allows movement of air and mucus in between the nose and sinuses.
Types of Sinus Infections
There are two main types of sinusitis: acute and chronic.
Acute sinusitis is diagnosed when symptoms have lasted no longer than four weeks.
Chronic sinusitis is diagnosed when symptoms have lasted for at least 12 weeks, despite medical treatment.
Sinusitis may also be classified as subacute sinusitis and recurrent sinusitis.