When the delicate tissues in the sinus cavities are inflamed, it results in sinus infection, or as it is medically called sinusitis or rhinosinusitis. Most cases of inflammation result from virus or bacteria incursion or of allergies. The inflammation triggers the build-up of mucus and can lead to secondary infection. The usual signs of sinus infection are facial pain, nasal discharge, and obstruction in the nasal passages, which persists for at least 7 days.

The sinuses are air-filled cavities lined with a thin layer of mucus in the skull. When inflamed, they become swollen and can no longer drain the mucus. This results in the accumulation of mucus, which can pose a breathing when breathing.

Sinusitis can be classified as acute (if it doesn’t last for more than 4 weeks), sub-acute (if not lasting for over 12 weeks), and chronic (if it exceeds 12 weeks). Majority of sinusitis cases are viral and may not require antibiotic treatment. However, antibiotics may be required for bacterial sinusitis. It is not the color of the phlegm that determines whether or not a sinus infection is bacterial.

As a sinusitis symptom, facial pain may be felt around the eyes, nose, and forehead. Sometimes, some discomfort may be felt in the teeth. There may also be throbbing headache, which may worsen when the patient bends down or strains. Nasal discharge may appear as green, yellow, or cloudy and is generally foul-smelling.

Other symptoms of sinus infection include fever, loss of smell, cough, post-nasal drip, bad breath, fatigue, and nausea.