• Clinical science



Sinusitis is an inflammation of the mucous membrane of the paranasal sinuses. It rarely occurs without concurrent inflammation of the nasal mucosa (rhinitis) and is therefore commonly referred to as rhinosinusitis. While the etiology is typically viral, it may also be bacterial or fungal (especially in immunocompromised patients). The condition is usually self-limiting, but if it lasts longer than 12 weeks it is considered chronic. The primary symptoms are purulent rhinorrhea and facial pain (particularly when leaning forward). Antibiotic therapy is only indicated if a bacterial superinfection is suspected. Imaging and endoscopy is reserved for cases that persist or worsen despite initial antibiotic therapy. Local extension of the disease may occur in cases that are complicated or that have not received adequate treatment, potentially resulting in frontal bone osteomyelitis, meningitis, or brain abscess.




  • Incidence: Sinusitis is one of the most commonly diagnosed conditions in the USA, affecting an estimated 35 million individuals per year.
  • Peak incidence: early fall to early spring
  • Sex: >

References: [4]

Epidemiological data refers to the US, unless otherwise specified.




  • Sinusitis is triggered by three factors: obstruction of sinus drainage pathways (sinus ostia), ciliary impairment, and altered mucus quantity and quality → stasis of secretions inside the sinuses → proliferation of various pathogens → sinusitis
  • Recurrent, untreated/complicated acute sinusitis may lead to chronic sinusitis.


Clinical features

Condition Sinusitis Rhinitis Additional features
Acute viral rhinosinusitis
  • Sneezing, nasal congestion, rhinorrhea, and post-nasal drip
  • Hyposmia/anosmia
Acute bacterial rhinosinusitis
  • Persistent symptoms ≥ 10 days without clinical improvement OR
  • ≥ 3 initial days of severe symptoms, fever (> 39°), facial pain, or purulent nasal discharge OR
  • Symptoms initially improve and then worsen after 5–6 days (double worsening)

Fungal rhinosinusitis

  1. Noninvasive
    • Allergic fungal: features of asthma and other atopic manifestations
    • Fungal mycetoma: unilateral complaints; usually involves the maxillary sinus
  2. Invasive
    • Acute fulminant rhino-orbital-cerebral mucormycosis: epistaxis and dark ulcers on the septum, palate and turbinates; acutely ill with altered mental status
Chronic rhinosinusitis
  1. Allergic fungal: See “Fungal rhinosinusitis” above.
  2. Chronic rhinosinusitis with nasal polyps: See “Nasal polyps.”
  3. Chronic rhinosinusitis without nasal polyps: anatomical abnormalities (septal deviation, tumors), dental disease

Acute bacterial rhinosinusitis should be suspected in patients with a preexisting viral URTI and symptoms that do not improve after 10 days or worsen after initial improvement!


Subtypes and variants

Nasal polyps [9][10]

Primary ciliary dyskinesia [11][12]

You can memorize the cause of Kartagener syndrome by thinking of Kartagener's restaurant that only has 'take-out' service because there is no dine-in (dynein)!

Kartagener syndrome is a subtype of primary ciliary dyskinesia characterized by the triad of situs inversus, chronic sinusitis, and bronchiectasis.


Diagnosis of acute cases is usually established clinically. However, imaging or endoscopy should be considered if symptoms fail to improve within 7 days of diagnosis or worsen during the initial management of acute bacterial rhinosinusitis.

  • Laboratory tests: to determine underlying condition if suspected (e.g., nasal cytology allergic rhinitis, HIV test, sweat chloride test for cystic fibrosis)
  • Imaging
    • X-ray of sinuses; (poor sensitivity): decreased transparency of sinus, air-fluid levels may be seen
    • CT of sinuses (imaging modality of choice)
      • Soft tissue swelling, mucoperiosteal thickening, and air-fluid levels
      • Bony erosions and extension in cases of invasive mucormycosis infection
      • Fungus balls in the case of chronic aspergillosis infection
    • MRI may be considered to confirm soft tissue extension in invasive disease.
  • Nasal endoscopy

A clinical diagnosis of chronic sinusitis should be confirmed with objective documentation of sinonasal inflammation, which may be accomplished using anterior rhinoscopy, nasal endoscopy, or computed tomography.



Condition General approach Additional treatment
Viral infection
Bacterial infection

Fungal infection

References: [2][3][8]


Orbital and intracranial necrotic spread is especially common in invasive fungal sinusitis.


We list the most important complications. The selection is not exhaustive.

  • 1. Hwang PH, Patel ZM. Acute sinusitis and rhinosinusitis in adults: Clinical manifestations and diagnosis. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/acute-sinusitis-and-rhinosinusitis-in-adults-clinical-manifestations-and-diagnosis. Last updated November 8, 2016. Accessed February 16, 2017.
  • 2. Chow AW, Benninger MS, Brook I et al. IDSA Clinical Practice Guideline for Acute Bacterial Rhinosinusitis in Children and Adults. Clin Infect Dis . 2012; 54(8): pp. e72–e112. doi: 10.1093/cid/cis370.
  • 3. Rosenfeld RM, Piccirillo JF, Chandrasekhar SS, et al. Clinical Practice Guideline (Update), Adult Sinusitis Executive Summary. Otolaryngol Head Neck Surg. 2015; 152(4): pp. 598–609. doi: 10.1177/0194599815574247.
  • 4. Lucas JW, Schiller JS, Benson V. Summary Health Statistics for U.S. Adults: National Health Interview Survey, 2001. url: https://www.cdc.gov/nchs/data/series/sr_10/sr10_218.pdf Accessed February 16, 2017.
  • 5. Patel ZM, Hwang PH, Deschler DG, Calderwood SB, Bond S. Uncomplicated Acute Sinusitis and Rhinosinusitis in Adults: Treatment. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/uncomplicated-acute-sinusitis-and-rhinosinusitis-in-adults-treatment. Last updated January 15, 2017. Accessed April 19, 2018.
  • 6. Raz E, Win W, Hagiwara M, Lui YW, Cohen B, Fatterpekar GM. Fungal Sinusitis. Neuroimaging Clin N Am. 2015; 25(4): pp. 569–576. doi: 10.1016/j.nic.2015.07.004.
  • 7. Morcom S, Phillips N, Pastuszek A, Timperley D. Sinusitis. Aust Fam Physician. 2016; 45(6): pp. 374–7. pmid: 27622225.
  • 8. Rosenfeld RM, Piccirillo JF, Chandrasekhar SS et al. Clinical practice guideline (update): Adult sinusitis. Otolaryngol Head Neck Surg. 2015; 152(2S): pp. S1–S39. doi: 10.1177/0194599815572097.
  • 9. Stevens WW, Schleimer RP, Kern RC. Chronic Rhinosinusitis with Nasal Polyps. The Journal of Allergy and Clinical Immunology: In Practice. 2016; 4(4): pp. 565–572. doi: 10.1016/j.jaip.2016.04.012.
  • 10. Hulse KE, Stevens WW, Tan BK, Schleimer RP. Pathogenesis of nasal polyposis. Clinical & Experimental Allergy. 2015; 45(2): pp. 328–346. doi: 10.1111/cea.12472.
  • 11. Lucas JS, Burgess A, Mitchison HM, et al. Diagnosis and management of primary ciliary dyskinesia. Arch Dis Child. 2014; 99(9): pp. 850–856. doi: 10.1136/archdischild-2013-304831.
  • 12. Shapiro AJ, Davis SD, Polineni D, et al. Diagnosis of Primary Ciliary Dyskinesia. An Official American Thoracic Society Clinical Practice Guideline. Am J Respir Crit Care Med. 2018; 197(12): pp. e24–e39. doi: 10.1164/rccm.201805-0819st.
  • 13. Levy DA, Pecha PP, Nguyen SA, Schlosser RJ. Trends in complications of pediatric rhinosinusitis in the United States from 2006 to 2016. Int J Pediatr Otorhinolaryngol. 2020; 128: p. 109695. doi: 10.1016/j.ijporl.2019.109695.
  • 14. Carr TF. Complications of sinusitis. American Journal of Rhinology & Allergy. 2016; 30(4): pp. 241–245. doi: 10.2500/ajra.2016.30.4322.
  • Bergström SE. Primary Ciliary Dyskinesia (Immotile-cilia Syndrome). In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/primary-ciliary-dyskinesia-immotile-cilia-syndrome. Last updated January 19, 2018. Accessed February 20, 2018.
last updated 09/24/2020
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