What Is Fungal Sinusitis?

You may have experienced waking up to pains or pressure between your eyes and other areas around your sinus without any prior warning. This feeling could be a sign of fungal sinusitis or one of its variants. 

Fungal sinusitis or fungal rhinosinusitis is a type of sinusitis caused by a fungus infection. Different kinds of fungal sinus infections have similar symptoms. Examples include nasal congestion and sinus pain in the cheeks, forehead, and between the eyes, which account for the top reason for the prescription of antibiotics.

In this article, we will discuss what fungal sinusitis is, how to manage or treat it, and also try to answer a few questions you may have been asking yourself.


The sinus is a series of spaces filled with air in the bones of the skull and face that link to the nasal cavity. These spaces house the mucous membranes that produce mucus, which helps to moisturise and protect the nasal cavities and also to warm and filter the air we breathe in.1

The sinus runs across the forehead, between the eyes, behind the nose, and under the cheekbones. The mucus layer on the sinus walls traps bacteria and keeps the air inside moist. Sinuses must drain regularly. The sinuses do not function as they should when there is a blockage or inflammation. This phenomenon is known as sinusitis.

Sinusitis is among the most common medical complaints and the leading cause of antibiotic prescriptions. The causes are a mix of environmental and internal factors. Acute sinusitis is typically caused by viruses and resolves independently without medication. Approximately 90% of patients who have colds have viral sinusitis. Those prone to allergies (atopy) will usually get sinusitis. Allergens, irritants, viruses, fungi, and bacteria can all cause it. Animal dander, polluted air, smoke, and dust are common environmental irritants.1,2

Fungal sinusitis or fungal rhinosinusitis is a sinus infection caused by fungi. It can be divided into two types: invasive fungal sinusitis and non-invasive fungal sinusitis.3,4

  • Non-invasive fungal sinusitis (NFS) is more common and usually not severe. It has three subtypes:
    • Fungal ball (FB), also known as eumycetoma due to a build-up of fungi in the sinus forming a ball or clump
    • Saprophytic fungal sinusitis (SFS) occurs when fungi grow on dried mucus in the nose but does not affect the tissue of the nose
    • Allergic fungal rhinosinusitis (AFRS) is caused by an allergic reaction. People with hay fever and asthma are susceptible to this
  • Invasive fungal sinusitis (IFS) is rare but can be life-threatening, especially in people with weakened immune systems. It also has three subtypes: 
    • Acute invasive rhinosinusitis (AIRS), also known as acute invasive fungal sinusitis and mucormycosis, is a potentially fatal condition more common in people with a compromised immune system. The infection can spread quickly to the eyes and brain, resulting in blindness and death
    • Chronic invasive rhinosinusitis (CIRS) is similar to AIRS but does not spread as quickly. It mostly affects people with diabetes 
    • Granulomatous invasive sinusitis (GIFS) is a rare type of IFS. It occurs when the body launches an immune response to fungi; however, during this attack, it also attacks the nasal lining and destroys the nasal tissue

Causes of fungal sinusitis

The fungi that cause fungal rhinosinusitis are commonly found in the environment and are harmless in small amounts. They can, however, cause an infection if they grow in excess, and exposure to these fungi causes fungal sinusitis. Fungi can enter the body through the nose, mouth, or skin.  People with a deficient immune system are more likely to get fungal sinusitis because their bodies have a decreased ability to fight infections. Exposure to certain environmental factors and previous sinus surgery can also increase the risk of fungal sinusitis.

Signs and symptoms of fungal sinusitis

Some of the symptoms of fungal sinusitis are:

  • A bad odour in the nose or a loss of smell
  • Fever
  • Runny nose
  • Nasal congestion
  • Swelling in the nose or sinus
  • Tenderness, pain, and pressure around the sinus
  • Headache in the sinus

Depending on the type of fungal infection, the signs and symptoms of fungal sinusitis may vary. The symptoms of non-invasive fungal sinusitis are similar to those of a typical sinus infection and include nasal congestion, sinus pressure, facial pain, and a runny nose. Invasive fungal sinusitis, on the other hand, can result in more severe symptoms such as fever, headache, facial swelling, and vision problems.4

People with weakened immune systems stand a higher risk of developing serious fungal sinusitis symptoms different from the normal symptoms, and these include:

  • Behavioural changes and neurological issues, such as difficulty in thinking
  • Facial numbness
  • The skin may become black or very pale
  • Eyeballs protrude or stick out from the eye sockets (proptosis)
  • Significant swelling in the eyes or cheeks
  • Vision changes, vision loss, or blindness

Management and treatment for fungal sinusitis

Your healthcare provider will perform a physical exam to diagnose a fungal sinus infection. They will inquire about your symptoms, medical history, and medications. Then, your doctor may remove some mucus or tissue from your sinuses and send it to a lab.

The treatment for fungal sinusitis depends on the type and severity of the infection. Mild cases of AFS may be treated with nasal corticosteroids and antifungal medications. More severe cases of AFS and IFS may require surgery to remove infected tissue and drain the sinus cavities.5 It is essential to seek medical attention promptly to prevent complications and minimise the risk of further infections.


How is fungal sinusitis diagnosed?

Fungal sinusitis is typically diagnosed through laboratory tests to determine the specific type of fungus causing the infection. Your doctor may also collect a sample of sinus tissue for further analysis. Additionally, a combination of imaging tests, such as CT scans or MRIs, may also be carried out. 

How can I prevent fungal sinusitis?

Preventing fungal sinusitis entails taking precautions to avoid being exposed to fungi spores, especially in environments where these spores are likely present. Preventive measures include ensuring good ventilation in damp or humid environments, wearing a mask when cleaning mouldy areas, and avoiding extended exposure to areas with significant fungal spores.

Who are at risk of fungal sinusitis?

People in contact with fungi spores, those prone to allergies, and those with weakened immune systems, such as HIV/AIDS or undergoing chemotherapy, are more likely to develop fungal sinusitis.  

How common is fungal sinusitis?

Fungal sinusitis is a fairly uncommon condition, accounting for only 2-7% of all sinusitis cases. It affects mostly children younger than 15 and adults aged 25 to 64.

When should I see a doctor?

If you have symptoms such as pain in the face or pressure, a headache, or nasal congestion, you should see a doctor to determine what the problem could be. If you have a compromised immune system or other underlying medical conditions, you are more likely to develop fungal sinusitis and should seek medical attention immediately if you suspect it.


Fungal sinusitis is a condition that arises from fungi growing in the sinuses, causing inflammation and other sinusitis symptoms. Imaging studies and laboratory tests are typically used to identify the fungus causing the infection. To avoid fungal sinusitis, avoid exposure to fungal spores, especially in environments where they are likely present. Certain individuals, for example, those with a weakened immune system, may be more vulnerable to fungal sinusitis. If you suspect you have this condition, seek medical attention as soon as possible to receive an accurate diagnosis and treatment.


  1. Henson B, Drake TM, Edens MA. Anatomy, Head and Neck, Nose Sinuses. [Updated 2022 Jul 25]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK513272/
  2. Battisti AS, Modi P, Pangia J. Sinusitis. [Updated 2023 Mar 2]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK470383/
  3. DeBoer DL, Kwon E. Acute Sinusitis. [Updated 2022 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK547701/
  4. Deutsch, Peter George, et al. “Invasive and Non-Invasive Fungal Rhinosinusitis—A Review and Update of the Evidence.” Medicina, vol. 55, no. 7, June 2019, p. 319. DOI.org (Crossref). Available from: https://doi.org/10.3390/medicina55070319
  5. Singh, Virendra. “Fungal Rhinosinusitis: Unravelling the Disease Spectrum.” Journal of Maxillofacial and Oral Surgery, vol. 18, no. 2, June 2019, pp. 164–79. DOI.org (Crossref), https://doi.org/10.1007/s12663-018-01182-w
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Chimezirim Ozonyiri

Bachelor of Science - BS, Microbiology, General, Tansian University, Nigeria

Chimezirim has several years of experience in the healthcare, non-profit, and education sectors. She is passionate about health promotion and began her journey into health and lifestyle writing over two years ago.

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