The sinuses are hollow pockets in the skull that are covered with a mucous coat and mucus usually drains out from the nose. When the sinuses are infected, they fill up with mucus as they become inflamed and swollen, thereby blocking the flow of mucus out of the sinuses. The build-up of mucus leads to sinusitis.
Sinusitis affects people of all ages. There are 2 types of sinusitis:
- Acute sinusitis, also known as acute rhinosinusitis, which lasts up to 4 weeks
- Chronic sinusitis, which lasts for at least 8 weeks despite treatment