Sinuses are air-filled spaces in the skull. Sinuses are connected to the nose, allowing the mucus produced in them to drain out through the nose.

In sinusitis, the lining of the sinuses becomes inflamed and swollen. This obstructs the flow of mucus out of the sinuses, leading to a build-up of mucus.

Unlike allergic rhinitis, sinusitis is often caused by viral, bacterial or fungal infections, instead of by allergens.

“Sinusitis caused by viruses usually resolves fairly quickly with just symptomatic treatment. For longer-lasting sinusitis, a bacterial infection is usually the cause and can be treated with oral antibiotics. Invasive fungal sinusitis – the least common of the three – usually occurs in patients with a weakened immune system,” say ​doctors ​from the ​​Department of Otolaryngology​​ at Singapo​​re General Ho​spital​ ​(SGH), a member of the SingHealth​​ group.​​

The primary symptom of sinusitis is nasal obstruction or congestion, with additional symptoms such as:

1. Throbbing pain in the cheeks and forehead area between the eyes (facial pain)
2. Sensation of fullness in the face
3. ​​Thick yellowish or greenish nasal discharge – there may be mucus dripping at the back of the throat, often resulting in coughing
4. Unilateral symptoms
5. Loss of smell
6. Purulent nasal discharge

Other symptoms that some may experience include:

1. Aching​ pain in the jaw, teeth or ears
2. Reduced sense of smell and taste
3. Fever
4. Nausea
5. Fatigue

Depending on the duration of the infection, sinusitis can be classifi​ed as either:

• Acute: When symptoms last up to 12 weeks
• Chronic: When symptoms last more than 12 weeks

Ref: O17​