1. Almost all causes of sinusitis are viruses (Human Respiratory Syncytial Virus, Parainflueza Virus, Metapneumo Virus), bacteria (Streptococcus pneumoniae, Haemophilus influenzae) and fungi.
2. Sinusitis occurs when the immune system is reduced due to fungal attack.
3. Allergies can cause this disease.
4. If the nasal passages are narrowed or blocked and if there is a polyp or lump inside the nose.
5. A tooth infection or a sinus infection due to tooth extraction.
6. If the dirty water enters the nasal sinuses if the dirty water is splashed.
7. If the nasal bones are bent or cracked.
8. This disease occurs when the tonsils behind the nose are enlarged.
9. Sinusitis occurs when the airways are narrowed as a result of inflammation of the nasal mucosa or when the sinus cavity is blocked by an abnormality of the septum.
10. Cystic fibrosis is caused by the gene.
11. Chronic sinusitis occurs when the Eustachian tube is abnormal and obstructed.
12. Sinusitis is caused by malnutrition, cold, pollution and damp environment.