What Is Fungal Sinusitis?

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Fungal sinusitis, or fungal sinus infection, refers to an infection that causes inflammation of the sinuses (hollow, air-filled spaces between your eyes, near your eyes, nose, cheeks, and forehead).

It occurs when you inhale microscopic fungi that thrive in warm and damp environments. These include outdoors (on plants and in the soil), indoors (in the air and on surfaces), and within the human body (on skin or internally). Of the 1.5 million to 5 million fungal species, only a few hundred cause infections in humans.

While only a handful of fungal species cause illness, such as fungal sinusitis, in healthy adults, it can be serious and potentially fatal to some. This is especially true for people with underlying health conditions, such as diabetes, leukemia (blood cancer), human immunodeficiency virus (HIV) or AIDS, and/or are immunocompromised (have a weakened immune system).

This article will explain the details of fungal sinusitis, including symptoms, causes, diagnosis and tests, management and treatment, prevention, outlook, and when to see a healthcare provider.

Fungal sinusitis can cause facial pressure and headache

Hiraman / Getty Images

What Is Fungal Sinusitis?

Sinusitis, or a sinus infection, is typically viral by nature, although some cases can be caused by bacteria. Fungal sinusitis is a uncommon infection that is specifically caused by a fungus.

Although the immune system can fight off many fungal infections, certain types of fungal sinusitis are life-threatening, especially in individuals with underlying health conditions and/or are immunocompromised.

What Is a Fungus?

A fungus (plural fungi) is a microscopic organism that can be found in a diverse range of habitats, including soil, air, water, on the skin, as well as in the foods that you eat. Common fungi include mushrooms, yeasts, mildews, and molds.

Fungi can grow in a wide range of temperatures (41 to 98.6 degrees Fahrenheit), but they grow best between 77 and 86 degrees, in conditions that are warm and damp.

At temperatures below 41 degrees, fungi do not grow well as their metabolic activity slows. They also do not grow well above 114 degrees due to high metabolic activity that can stress the fungi, making them die. For these reasons, fungal growth is prevalent in the summer and decreases in the winter.

What Are the Sinuses?

The sinuses are air-filled spaces near your nose, eyes, cheeks, and forehead. There are four different sinuses (parasinuses), and each is lined with mucous membranes. They include the ethmoid sinus, maxillary sinus, frontal sinus, and sphenoid sinus.

The primary function of the sinuses is to produce mucus that traps debris (dirt, dust) and pathogens (disease-causing organisms). Doing so prevents them from being inhaled directly into the lungs.

If your sinuses are blocked, an infection may develop. This causes mucus to thicken and change in color (from clear to yellow or green), depending on the stage of infection.

Types of Fungal Sinusitis

There are two classes of fungal sinusitis: noninvasive (NFS) and invasive (IFS), each having different subtypes. Each subtype is classified based on the level of fungal invasion in the sinuses.

There are three subtypes of NFS, which include:

  • Allergic fungal rhinosinusitis (AFRS)
  • Fungal ball sinus infection (mycetoma)
  • Saprophytic fungal sinusitis (SFS)

There are also three subtypes of IFS, which include:

  • Acute fulminant invasive rhinosinusitis (AFIRS)
  • Chronic invasive rhinosinusitis (CIRS)
  • Granulomatous invasive sinusitis (GIFS)

Noninvasive Fungal Sinusitis (NFS)

NFS are generally not life-threatening, as they do not invade tissues beyond the sinuses. They are also typically caused by environmental fungi that trigger allergies.

Allergic Fungal Rhinosinusitis (AFRS)

AFRS is a common type of fungal sinusitis that affects adolescents and young adults. It occurs when fungi (primarily Aspergillus) are inhaled from the environment and trigger an allergic reaction in the body.

Common symptoms of AFRS include a stuffy or runny nose with a thick peanut butter–like discharge, headaches, facial tension, blocked tear duct (irritated, watery eyes), and in some cases, loss of the sense of smell (anosmia).

Fungal Ball Sinus Infection (Mycetoma)

A fungal ball sinus infection, or mycetoma, is a condition in which fungal hyphae (filaments) accumulate in the sinuses and form fungal balls. If left untreated, these balls can grow bigger and block the sinuses, causing facial pain, swelling, and tenderness. Fungal balls can also trap bacteria, which can lead to a secondary bacterial infection.

Saprophytic Fungal Sinusitis (SFS)

Saprophytic fungal sinusitis occurs when fungi colonize the mucus or mucus crust in your nose. They do not affect the nasal tissue and can therefore be asymptomatic and difficult to diagnose. A key feature of this type of sinusitis is a foul odor in your nose.

Invasive Fungal Sinusitis (IFS)

IFS is a serious condition that typically occurs in people with an underlying health condition and/or are immunocompromised. IFS is classified as acute or chronic and can destroy nasal tissue. The acute form of IFS is life-threatening, as it spreads quickly throughout the blood vessels and central nervous system (CNS), which includes the brain and spinal cord.

Chronic IFS, however, spreads more slowly throughout the bloodstream. For this reason, it can be commonly mistaken for a viral or bacterial infection.

Common symptoms of acute and chronic IFS include:

  • Fever
  • Headache
  • Pain, swelling, or tenderness in the face
  • Cough
  • Runny, stuffy nose
  • Reduced or loss of smell
  • Foul smell in the nose
  • Vision changes
  • Altered mental status (confusion/disorientation, impaired memory, and emotional fluctuation)

Medical Emergency

Both acute and chronic IFS can be serious. However, acute IFS is a potentially fatal medical condition in which fungi spread quickly throughout the bloodstream. If you experience any of the symptoms of IFS, seek immediate medical attention.

Acute Fulminant Invasive Rhinosinusitis (AFIRS)

AFIRS is a rare and aggressive condition with high morbidity (illness in a population) and mortality (death) rates. It typically occurs after inhaling fungi, which can grow on the mucus lining of the nose and sinuses. From there, it can rapidly spread to the eyes and brain and cause the destruction of tissues along the way.

In general, AFIRS can cause serious complications, which include:

  • Hyphal invasion of blood vessels (which can lead to death in the surrounding tissues)
  • Vasculitis (inflammation of the blood vessels)
  • Thrombosis (blood clots)

Mortality Rates of AFIRS

Studies show that the mortality rate of AFIRS is approximately 50% for those with the presence of an underlying health condition, including liver failure and changes in mental status. Better survival outcomes were seen in individuals with diabetes who underwent surgery or who received antifungal medication (amphotericin B).

Chronic Invasive Rhinosinusitis (CIRS)

CIRS is a rare condition characterized by a very slow onset of symptoms and progression of disease (usually months). It is similar to AFIRS, but occurs far more slowly. CIRS typically affects individuals with diabetes or recipients of organ transplants. Common symptoms include a stuffy nose, facial tension and pain, and headaches.

Because the progression of CIRS is very slow, early diagnosis is essential and potentially lifesaving. If left untreated, CIRS can cause an altered mental status and seizures.

Granulomatous Invasive Fungal Sinusitis (GIFS)

GIFS is a rare and unusual condition that affects the parasinuses and can lead to bone destruction. GIFS cases are prevalent in regions of the world with dry climates, including Sudan, India, and Saudi Arabia. Unlike other types of invasive fungal sinusitis, GIFS primarily affects healthy individuals.


The incidence (rate or frequency of disease) of fungal sinusitis depends on the type of infection you have. Noninvasive cases typically occur more frequently than invasive cases. For example, some studies show that the incidence rate of AFRS is 30%.

Symptoms and Causes of Fungal Sinusitis

Although symptoms vary depending on the type of fungal sinusitis you have, the list below shows common symptoms, including the cause of the disease.

What Are the Symptoms of Fungal Sinusitis?

Common symptoms of fungal sinusitis include:

  • Fatigue
  • Loss of smell or taste
  • Stuffy nose
  • Runny nose
  • Pain or pressure in face and sinuses

What Causes Fungal Sinusitis?

Fungal sinusitis occurs when you inhale fungi into your nose, sinuses, and lungs. Aspergillus, a common environmental mold, accounts for the majority of fungal sinusitis cases.

Diagnosis and Testing of Fungal Sinusitis

To evaluate for the presence of fungal sinusitis, your healthcare provider will examine your head and neck using a nasal endoscope (camera that looks into the nasal cavity and surrounding sinuses).

While computed tomography (CT) scans are used in most cases to check for the degree of invasion, magnetic resonance imaging (MRI) scans are the preferred method for IFS cases, as they can identify growth in soft tissue.

A sample of mucus or pus in the nose may also be taken and sent to the lab to check for the presence of fungi. This procedure is commonly performed in NFS cases in which fungi do not invade the bloodstream.

Management and Treatment of Fungal Sinusitis

Treatment of fungal sinusitis depends on the type of infection you have and whether you have an underlying health condition and/or are immunocompromised. Common treatments for sinusitis include antifungal medications, sinus surgery, a nasal wash, and corticosteroid medications.

Antifungal Medication

Antifungal medications are typically used to treat noninvasive fungal infections by preventing or stopping fungal growth and replication in the body.

There are three classes of antifungal medications that are used clinically, which include polyenes (rupture cell membranes), triazoles (inhibit the formation of cell membranes), and echinocandins (inhibit the formation of cell walls). These medications can be injected, taken intravenously, or taken orally (in a pill or liquid form).

Sinus Surgery

Sinus surgery is commonly used in invasive cases of fungal sinusitis and involves the removal of dead tissue in the sinuses. It can also be used in noninvasive cases to remove fungal balls.

Nasal Wash

A nasal wash typically consists of a saline solution (mixture of water and salt) that is used to remove accumulated mucus that is blocking nasal passages and sinuses. It is commonly used to treat cases of noninvasive fungal infections.

Corticosteroid Medications

Corticosteroids are medications that reduce nasal pressure and inflammation in the sinuses. They are frequently recommended in the treatment of allergic fungal rhinosinusitis. However, long-term usage of corticosteroids can be harmful, as they increase your chances of fungal infections. Speak with your healthcare provider about using corticosteroids to provide short-term relief.


You can prevent fungal sinusitis by using similar methods to prevent a sinus infection caused by viruses and bacteria. They include:

  • Nasal irrigation: Gently run sterile saline through your nasal passages to remove debris, pathogens, and excess mucus. Saline solution lubricates nasal passages to prevent cracks in the membranes where fungus can enter.
  • Stay hydrated: Drinking plenty of water each day can moisten nasal passages and keep mucus thin and loose.
  • Practice good hygiene: Wash your hands for at least 20 seconds to eliminate dirt and germs.
  • Avoid sharing personal items: This includes clothing, towels, and masks.


With early treatment, most cases of noninvasive fungal sinusitis can be easily managed, even if they recur.

However, the outlook of acute invasive fungal sinusitis is generally poor even with aggressive medical intervention. Studies show that mortality rates for AFIRS is approximately 50%.

It is imperative to seek immediate medical attention if you have an underlying health condition and/or are immunocompromised, as an early diagnosis may increase the odds of survival.

When to See a Healthcare Provider

Seek medical attention if you suspect a sinus infection or if your symptoms aren't improving. Because fungal infections can be difficult to treat if they become systemic (widespread), early diagnosis is crucial.


Fungal sinusitis refers to a range of infections that cause inflammation of the sinuses. It occurs when you inhale microscopic fungi that can be found in warm and damp environments. Certain types of fungal sinusitis are life-threatening, especially in individuals with underlying health conditions and/or are immunocompromised.

There are two classes of fungal sinusitis: noninvasive (NFS) and invasive (IFS), each having different subtypes. Each subtype is classified based on the level of fungal invasion in the sinuses.

Treatment of fungal sinusitis depends on the type of infection you have and how healthy you are. Common treatments for sinusitis include antifungal medications, sinus surgery, nasal wash, and corticosteroids.

A Word From Verywell

Most cases of sinusitis due to viruses or allergies can be treated and self-managed at home. However, if you suspect a fungal sinus infection and have an underlying condition and/or are immunocompromised, do not delay seeking medical attention. If left untreated, invasive fungal sinusitis can be potentially fatal.

Frequently Asked Questions

  • What symptoms should make you suspect a sinus infection is fungal?

    If you have a reduced sense of smell or if you have experienced a foul odor in your nose, you may have a sinus infection that is fungal.

  • Can a CT scan detect fungal sinusitis?

    A CT scan can detect fungal infection of the paranasal sinuses with high accuracy. It can also reveal the extent of the disease to determine the best course of treatment.

  • What fungi causes sinusitis?

    Although many types of fungi can cause sinusitis, Aspergillus mold causes the most cases.

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