What causes sinusitis (sinus infection)?

Updated: Mar 01, 2018
  • Author: Itzhak Brook, MD, MSc; Chief Editor: Michael Stuart Bronze, MD  more...
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Answer

Purulent sinusitis can occur when ciliary clearance of sinus secretions decreases or when the sinus ostium becomes obstructed, which leads to retention of secretions, negative sinus pressure, and reduction of oxygen partial pressure. This environment is then suitable for growth of pathogenic organisms. Factors that predispose the sinuses to obstruction and decreased ciliary function are allergic, nonallergic, or viral insults, which produce inflammation of the nasal and sinus mucosa and result in ciliary dysmotility and sinus obstruction.

In individuals with recurrent or persistent sinusitis, suspect other predisposing conditions such as cystic fibrosis, ciliary dyskinesia, allergic inflammation, immunodeficiency, or an anatomic problem. These predisposing factors are also cited by the 2005 practice parameter for diagnosis and management of sinusitis issued by the American Academy of Allergy, Asthma and Immunology (AAAAI), as are cocaine addiction and nasal polyps and other causes of ostiomeatal obstruction. [2]


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