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What is chronic rhinosinusitis?

Sinuses are hollow, connected cavities in the skull located in the cheekbones, forehead, between the eyes, and in bones behind the nose. It is believed that sinuses help humidify and filter the air we breathe in. Normally, these cavities are lined with a thin layer of mucus and are otherwise empty. Chronic rhinosinusitis (CRS, or sinusitis) occurs when the lining of the nose and sinuses is constantly inflamed. This often results in mucus building up in the sinuses and an uncomfortable sensation of pressure in the front of the face.1,2 CRS can severely impact quality of life and make it difficult to work.1

About 10-15% of people worldwide have CRS. According to The National Health Interview Survey, 12.1% of adults in the US had CRS in 2012.3

What are common symptoms?

A doctor may diagnose you with CRS if you have been experiencing two or more of the main symptoms for at least 3 months. These main symptoms include4:

  • Nasal congestion caused by mucus
  • Nasal drainage
  • Loss of smell
  • Facial pain or sensation of pressure

Other symptoms include headache, fever, coughing, bad breath, fatigue, ear fullness, ear pain, and ear pressure. As CRS worsens, it can change the structure of the sinuses, leading to asthma and migraines.4

You may be at risk for CRS if you have any of the following (in order of frequency)5:

  • Allergies
  • Deviated septum and other changes to facial structure
  • Asthma
  • Aspirin sensitivity
  • Immune system disorders
  • Viral infections
  • Sinus surgery history

You may also be at risk of CRS if you have been exposed to one or more of these conditions (in order of frequency)5,6,7:

  • Smoking
  • Air pollutants
  • Damp environments
  • Wintery conditions

What are the causes?

Though we don’t yet know the exact cause of CRS, scientists have some theories. The environment you live in may affect whether you develop the disease. For example, researchers are studying whether certain fungi and bacteria can trigger the disorder. How well your immune response functions may also affect your likelihood of developing CRS. If your immune response is defective, your skin barrier may not function properly and you may struggle to clear your respiratory tract. These factors may work together to cause inflammation in your nose and sinuses and eventually cause CRS to develop.2,8

How does this topic relate to my microbiome?

Scientists are using new, advanced techniques to explore the relationship between CRS and a dysfunctional nasal microbiome.8 Studies generally show that CRS patients have an unhealthy microbiome in their sinuses, with lower microbial diversity, compared to healthy controls. Healthy individuals’ nasal microbiota are mostly populated by the phyla Propionibacterium, Actinobacter, or Burkholderia. Scientists believe that these bacteria help maintain a stable microbiota in the sinuses and can prevent CRS from developing or progressing. The bacteria most commonly associated with CRS are those belonging to the phylum Staphylococcus (especially S. aureus), Corynebacterium, and Streptococcus.9,10

Which diseases/topics are related to chronic rhinosinusitis?

Since CRS involves inflammation, it is associated with several other respiratory conditions, including:

  • Asthma
  • Allergic rhinitis
  • Chronic obstructive pulmonary disease (COPD)
  • Influenza
  • Viral upper respiratory infections

How can I take action?

Chornic rhinosinusitis patients often need lifelong treatment to control their symptoms. Some measures you can take on your own if you suffer from CRS are (in order of importance)11:

  • Quitting smoking
  • Reducing exposure to allergens at home and in the workplace
  • Washing nasal passages with saline solution

For a correct evaluation of your condition, visit your healthcare provider. Depending on what is causing your CRS, they may recommend:

  • Allergy treatments
  • Antibiotics, if a bacterial infection is causing your CRS
  • Glucocorticoid treatment (intranasal or oral)
  • Surgery, if your CRS is severe, or caused by anatomic problems or nasal polyposis11


1. Tomassen, P., Zele, T. V., Zhang, N., Perez-Novo, C., Bruaene, N. V., Gevaert, P., & Bachert, C. (2011). Pathophysiology of Chronic Rhinosinusitis. Proceedings of the American Thoracic Society, 8(1), 115–120.

2. Stevens, W. W., Lee, R. J., Schleimer, R. P., & Cohen, N. A. (2015). Chronic rhinosinusitis pathogenesis. Journal of Allergy and Clinical Immunology, 136(6), 1442–1453.

3. DeConde, A. S., & Soler, Z. M. (2016). Chronic rhinosinusitis: Epidemiology and burden of disease. American Journal of Rhinology and Allergy, 30(2), 134–139.

4. Sundaresan, A. S., Hirsch, A. G., Young, A. J., Pollak, J., Tan, B. K., Schleimer, R. P., … Schwartz, B. S. (2018). Longitudinal Evaluation of Chronic Rhinosinusitis Symptoms in a Population-Based Sample. Journal of Allergy and Clinical Immunology: In Practice, 6(4), 1327–1335.e3.

5. Tint, D., Kubala, S., & Toskala, E. (2016). Risk Factors and Comorbidities in Chronic Rhinosinusitis. Current Allergy and Asthma Reports, 16(2), 16.

6. Ahlroth Pind, C., Gunnbjörnsdottír, M., Bjerg, A., Järvholm, B., Lundbäck, B., Malinovschi, A., … Janson, C. (2017). Patient-reported signs of dampness at home may be a risk factor for chronic rhinosinusitis: A cross-sectional study. Clinical & Experimental Allergy, 47(11), 1383–1389.

7. Mady, L. J., Schwarzbach, H. L., Moore, J. A., Boudreau, R. M., Willson, T. J., & Lee, S. E. (2018). Air pollutants may be environmental risk factors in chronic rhinosinusitis disease progression. International Forum of Allergy & Rhinology, 8(3), 377–384.

8. Lam, K., Schleimer, R., & Kern, R. C. (2016). The Etiology and Pathogenesis of Chronic Rhinosinusitis: a Review of Current Hypotheses, 15(7).

9. Wagner Mackenzie, B., Waite, D. W., Hoggard, M., Douglas, R. G., Taylor, M. W., & Biswas, K. (2017). Bacterial community collapse: a meta-analysis of the sinonasal microbiota in chronic rhinosinusitis. Environmental Microbiology, 19(1), 381–392.

10. Cleland, E. J., Bassiouni, A., Vreugde, S., & Wormald, P. J. (2016). The bacterial microbiome in chronic rhinosinusitis: Richness, diversity, postoperative changes, and patient outcomes. American Journal of Rhinology and Allergy, 30(1), 37–43.

11. Scadding, G. K., Durham, S. R., Mirakian, R., Jones, N. S., Drake-Lee, A. B., Ryan, D., … Nasser, S. M. (2007). The bacterial microbiome in chronic rhinosinusitis: BSACI guidelines for the management of rhinosinusitis and nasal polyposis. Clinical & Experimental Allergy, 38(2), 260–275.