Sinüzit is an inflammation of the sinuses, which are air-filled spaces in the skull. This condition can occur when the sinuses become blocked due to infections, allergies, or other factors. Symptoms often include nasal congestion, facial pain, and a reduced sense of smell. There are two main types of sinüzit: acute and chronic. Acute sinüzit lasts for a short period, usually less than four weeks, while chronic sinüzit persists for more than twelve weeks. Treatment may involve medications, such as decongestants or antibiotics, depending on the underlying cause.