Causes
By Mayo Clinic staffCommon causes of chronic sinusitis include:
- Nasal polyps or tumors. These tissue growths may block the nasal passages or sinuses.
- Allergic reactions. Allergic triggers include fungal infection of the sinuses.
- Deviated nasal septum. A crooked septum — the wall between the nostrils — may restrict or block sinus passages.
- Trauma to the face. A fractured or broken facial bone may cause obstruction of the sinus passages.
- Other medical conditions. The complications of cystic fibrosis, gastroesophageal reflux, or HIV and other immune system-related diseases may result in nasal blockage.
- Respiratory tract infections. Infections in your respiratory tract — most commonly, colds — can inflame and thicken your sinus membranes, blocking mucus drainage and creating conditions ripe for growth of bacteria. These infections can be viral, bacterial or fungal in nature.
- Allergies such as hay fever. Inflammation that occurs with allergies may block your sinuses.
- Immune system cells. With certain health conditions, immune cells called eosinophils can cause sinus inflammation.
References
- Rhinosinusitis: What is chronic rhinosinusitis? American Academy of Allergy Asthma & Immunology. www.aaaai.org/patients/publicedmat/sinusitis/whatischronicsinusitis.stm. Accessed Aug. 10, 2010.
- Jebreel A, et al. Chronic rhinosinusitis: Role of CT scans in the evaluation of paranasal sinuses. Internet Journal of Otorhinolaryngology. 2007;6:e1. http://www.ispub.com/ostia/index.php?xmlFilePath=journals/ijorl/vol6n2/ct.xml. Accessed Aug. 10, 2010.
- Hamilos D. Clinical manifestations, pathophysiology, and diagnosis of chronic rhinosinusitis. http://www.uptodate.com/home/index.html. Accessed Aug. 10, 2010.
- Hamilos D. Medical management of chronic rhinosinusitis. http://www.uptodate.com/home/index.html. Accessed Aug. 10, 2010.
- Wood AJ, et al. Pathogenesis and treatment of chronic rhinosinusitis. Postgraduate Medicine Journal. 2010;86:359.
- Guilemany JM, et al. Controversies in the treatment of chronic rhinosinusitis. Expert Review Respiratory Medicine. 2010;4:463.
- Naegleria FAQs. Centers for Disease Control and Prevention. http://www.cdc.gov/parasites/naegleria/faqs.html. Accessed Dec. 30, 2011.


Find Mayo Clinic on