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There are a variety of factors that may cause sinusitis and sinus congestion.

These include:     

  • viral, bacterial or fungal infections1,2,3     
  • allergic responses to dust, pollen or other allergens1,2,4    
  • anatomical/structural abnormalities2    
  • immunity problems2     
  • genetic factors5     
  • environmental factors like smoking, diving, swimming and high-altitude climbing2,5

It follows that sinusitis is therefore not always infectious. If, however, your sinusitis has been caused by a viral, bacterial or fungal infection, it may well be infectious.3 The problem is that even doctors and pharmacists may sometimes struggle to know what the cause is in individual patients.5,6

The most common cause of sinusitis is a viral infection.1,6 Viruses are often contagious and can be spread from person to person via coughing, sneezing, touching of hands, kissing, and so on.7,8 However, just because a virus can be transmitted to someone else doesn’t necessarily mean that it will cause a sinus infection in them too. We all respond differently to viruses.8

Experts disagree about whether sinusitis caused by a bacterial infection is contagious. Some medical websites claim that it is not.8,9 Others disagree,7 but as bacteria and fungi can be infectious agents,3 it is prudent to assume that bacterial- and fungal-related sinusitis may well be contagious.


Does green or yellow mucus mean I need an antibiotic or that my sinusitis is contagious?

A common misunderstanding is that having thick yellow or green excess mucus in your nasal passages and sinuses means you have a bacterial infection and therefore need an antibiotic. Evidence suggests, however, that cloudy or discoloured (brown, yellow or green) nasal mucus may be present in both bacterial and viral sinusitis1 and that mucus colour may therefore be a weak indicator of whether the infection is viral or bacterial.10


Strategies to prevent the spread of contagious sinusitis

As respiratory infections can be spread by coughing, sneezing and hand-to-hand contact, the most important way to prevent transfer of the infection is good hand-washing practices, using soap or alcohol-based rubs. This is particularly important when in contact with people who are unwell.1

Strategies to prevent non-contagious sinusitis

Minimise your exposure to environmental irritants, like cigarette smoke and pollutants, and to allergens, like dust and pollen.1

  1. BMJ Best Practice. Acute sinusitus. Last updated: 01 Mar 2019. Available at: Last accessed May 2019.
  2.  Ah-See KW and Evans AS. Sinusitis and its management. BMJ 2007; 334:358-361.
  3. Lau J et al. Diagnosis and treatment of acute bacterial rhinosinusitis: summary. In: Agency for Healthcare Researchand Quality (US) 1999. Available at: Last accessed May 2019.
  4. Helms S and Miller AL. Natural treatment of chronic rhinosinusitis. Altern Med Rev 2006; 11(3):196-207.
  5. BMJ Best Practice. Chronic sinusitis. Last updated: 21 Mar 2018. Available at: Last accessed May 2019.
  6. Scheid DC and Hamm RM. Acute bacterial rhinosinusitis in adults: part 1. Evaluation. Am Fam Physician; 70(9):1685-1692.
  7. MedicineNet. Is a sinus infection contagious? Symptoms, transmission (kissing), home remedy and treatment drugs, surgery, and cure. Last updated: 27 Nov 2018. Available at: Last accessed May 2019.
  8. WebMD. Are sinus infections contagious? Last updated: 13 Jun 2018. Available at: Last accessed May 2019.
  9. Healthline. Sinus infections: are they contagious? Last updated: 01 Jun 2017. Available at: Last accessed May 2019.
  10. Gonzales R et al. Principles of appropriate antibiotic use for treatment of nonspecific upper respiratory tract infections in adults: background. Clinical Practice Guideline, Part 2. Ann Intern Med 2001; 134:490-494.